Monday, July 21, 2014

The flower that makes me crave fried eggs

The 4 inch flowers of Romneya
coulteri
 look like a fried egg
cooked sunny-side up
Believe it or not, I actually had a very difficult time picking a plant to cover this week.  I knew that somewhere in Kew's 300 acres I should be able to find one plant that I find genuinely interesting, but inspiration never struck.  My group spent a couple days working in the Secluded Garden this week, and while we were working I kept running through plants in my mind, nixing some and earmarking others for later.

While I toiled away in mental anguish, visitors kept interrupting my train of thought to ask, "Excuse me please, what is the name of that plant?"  "What is that plant?"  "What do you call that plant?  That one on the other side of the water?"  Each group was asking about the same plant -- a large, shrubby poppy that was covered in white blooms growing just on the other side of the stream (1994-3738, SCON).  Nobody could seem to remember the genus, so every time someone would have to scurry down the embankment, ford the waters, and call back, "Romneya coulteri -- It's a kind of a poppy."

Finally, after four or five times, I thought to myself, "This may be a plant worth writing about."  And I wasn't disappointed.

Back to its roots

Romneya coulteri, or the canyon matilija poppy, is native to southern California.  Its range includes Los Angeles, Riverside, Ontario, and San Diego counties.  R. coulteri is perennial from USDA hardiness zones 7 to 11.  It thrives in chaparral and coastal shrub habitats -- especially in dry washes and canyons where the altitude is less than 1,200 meters (Hickman, 816). 

Seed head of R. coulteri.  The seeds of
this species of poppy actually
have a higher germination rate when
exposed to smoke caused by a fire
The matilija poppy may also be spotted in areas that have been affected by fire.  R. coulteri has adapted to fire damage in two ways.  First, shoots will easily re-sprout from the roots after the plant is burnt to the ground.  Second, exposure to smoke can actually increase seed germination (California, 239). 

This California native was first noted by a European in Baja during the early 1800's.  T. Romney Robinson was an Irish astronomer who had an eye for beauty in the sky and on the ground.  The genus was named Romneya in recognition of his discovery (Hickman, 816).

Today, the habitat of R. coulteri is threatened by urbanization, including new home and shop developments, roadside expansion, and flood control (California, 239). Both Kew's living collection database and the California Native Plant Society note that this is a rare plant in need of conservation.  The notes in Kew's database for both of their specimens of R. coulteri indicate that in 1997 this species was listed as endangered by the IUCN red list.  However, neither the CITES database nor the IUCN red list currently list it as endangered.

It looks like a fried egg

Just like all of our curious visitors, the feature of this plant that really stands out to me are the white and yellow blossoms.  Their 4 inch blooms look just like a fried egg cooked sunny-side up.  This species actually produces the largest flowers out of any of California's native plants.  That is especially compelling when you consider that the state of California is over 400,000 square kilometers and covers twenty-one distinct (and often wildly different) types of landscapes.

R. coulteri in the Papaveraceae section of the
Chelsea Physic Garden.  Notice how much taller
it is than the other poppies in the bed.
R. coulteri in cultivation is really floriferous.  I saw two specimens of the matilija poppy at Kew (2004-2746, PERH) and one at the Chelsea Physic Garden, and they were all totally laden with flowers. You can count on this plant flowering non-stop through the whole summer, from as early as May right up until the end of July.  The foliage is a very attractive soft, silvery blue.  Although the leaves vary in length, the deep lobes and cool color really softens the effect of the sunny blooms.

If you're picturing these flowers held on a plant that resembles other poppies, think again.  This is a big plant -- another common name for R. coulteri is tree poppy.  It isn't uncommon for the matilija poppy to grow upwards of 6 feet (2 meters) tall.  I haven't read anything on this, but I'd be interested to learn whether the plant sets flower buds on old or new growth.  This would dictate how you should prune to maintain size.  If it sets flowers on old growth, then all old stems that have already bloomed should be removed at the end of the growing season.  If it blooms on new wood, then it should be cut back hard to about 6 inches after the danger of frost has passed in the spring.  Or you could embrace this plant at its natural height and site accordingly.

Landscape value

Although the matilija poppy is native
to dry and sunny southern
California, it thrives in more cool,
moist and shady conditions
Although R. coulteri is native to a hot, dry Mediterranean type of climate, the plant is very adaptable in cultivation.  There's a specimen at Kew that is absolutely thriving in afternoon shade and relatively rich soil.  However, the matilija poppy may be more vigorous in environments that are similar to its native habitat, including the Mediterranean and areas in Africa, Australia, and so on.  It has been described as having weedy tendencies in southern California, so gardeners in similar climates have a responsibility to keep an eye on their specimens and report any invasive qualities.

The matilija poppy is at home towards the back of the flower border, where it is less likely to cover up smaller growing companions.  This plant doesn't have a lot of winter interest, so consider siting next to an evergreen, an ornamental grass, or a tree with interesting bark.  I think this plant would be the perfect fit for growing beneath a kitchen window.  The sunny blooms would really brighten the view and give a friendly reminder to enjoy a fried egg sunny-side up once in a while.

If you have any questions, comments or suggestions, please feel welcome to leave a comment or send me an email.

To see more photos from this week, be sure to check out the album "The flower that makes me crave fried eggs" on the Plante on Plants Facebook page.  "Likes", shares and comments are appreciated.

Pistil and stamen of Romneya coulteri
This poppy is sure to stand out in any landscape.  Notice how prominent the flowers are surrounded by the other colorful selections in Kew's Duke's Garden.
All photos and videos were taken by Amanda Plante at the Royal Botanic Gardens, Kew unless otherwise stated in the caption.

Sources:
  • (1994).  California Native Plant Society's Inventory of Rare and Endangered Vascular Plants of Califoria (5th ed.).  CNPS Special Publication, p. 239
  • Center for the International Trade in Endangered Species database
  • Dave's Garden Plant Files
  • Hickman, J.C.  (1993).  The Jepson Manual: Higher Plants of California (3rd printing). Berkley, CA: University of California Press, p. 816-817.
  • Kew's Living Collections database
  • Rundel, P.W. & Gustafson, R.  (2005).  California Natural History Guides Introduction to the Plant Life of Southern California: Coast to Foothills. Berkley, CA: University of California Press, p. 101-102
  • The International Union for Conservation of Nature and Natural Resources Red List of threatened species
  • The Plant List website
  • The Royal Botanic Gardens, Kew website and staff

Sunday, July 13, 2014

If you like pineapple lilies, you'll love Eucomis vandermerwei

Eucomis vandermerwei is currently
on display in Kew's Alpine House.
I love the purple spotted foliage!
When I first laid my eyes on a pineapple lily (Eucomis), it was love at first sight.  The bold foliage, the unique flower, and the really striking growth habit all do something for me.  My first experience was when Dr. Susan Hamilton had me do a mass planting of Eucomis comosa 'Sparkling Burgundy' in the back 40 of the University of Tennessee Gardens.  If I recall correctly, we had a little more than a dozen 3 inch pots left over from a plant sale, and we needed to find a home for them in the gardens.  The last time I strolled through the area, they were still there, bold and bright as could be.  In most gardens, pineapple lilies are usually planted singly as a focal point or foil, but en masse they're really something to shout about.

Last week, the interns at Kew were given a tour of the Alpine House, and I was head over heels all over again -- this time with Eucomis vandermerwei (2011-1894, RDRE).

It looks like a pineapple

This pineapple lily is unlike any other I've ever seen.  It has really attractive purple and green spotted foliage, and the leaves are a bit more strappy than the other species that I've seen before. Although it is given the common name because its flower looks a bit like a pineapple, the habit and foliage reminds me of pineapple plant too.

Both the common name and the scientific name describe the plant's unusual flower.  Eucomis is derived from the Greek meaning something like beautiful hair in a "top knot" style (Pearse, 38).

Native Range

In Mountain splendour: Wild flowers of the Drakensberg, Reginald Pearse describes the Eucomis as, "Essentially an African genus."  He goes on to write that most pineapple lilies harken from South Africa, many in the Natal region.  Wakehurst's specimen of E. vandermerwei was collected from the just north of the Natal in the Mpumalanga province.  Kew's live collections database notes that this plant was on the IUCN Red List as an endangered species in 1997.  Apparently it has made a comeback since then, as it is no longer listed.

This plant's common name is pineapple
lily, because the flower resembles that fruit.
The genus Eucomis refers to how the flower
resembles a beautiful "top knot" hairdo.
Unlike the other Eucomis that flourish in the grassy gullies of the coastal region, E. vandermerwei is an alpine plant.  In the wild, you will find this species in the rocky savannah on a high plateau.  This means that E. vandermerwei can survive winter frosts (USDA hardiness zones 6a - 8b).  However, the problem with cultivating this species in a North American or European garden doesn't stem from cold hardiness. 

When I saw this plant for sale this weekend at the Hampton Court Palace Flower Show, I decided to ask the vendor from Cornwall's Trecanna Nursery for some cultivation tips.  He told me the main reason why gardeners struggle to grow this plant is because of its water needs.  Although its native habitat does receive a fair amount of rainfall (one source lists about 24 inches or 640 mm annually), most of this occurs in the summer.  "I tell people to keep it in a pot and move it inside in the winter so it can dry out,"the nurseryman advised.

Landscape Value

If you live in an area that is similar to E. vandermerwei's native range, then I think that a clump of this plant would be a real show stopper.  If you're like me, and live in a place that has soggy winters, then it would be best to reserve yourself to one specimen in a container so that it will be easier to accommodate its finicky water needs.  

Although I'm sure it that combining this plant with a limey annual like a sweet potato vine, 'Rita's Gold' Boston fern, or 'Lime Zinger' elephant's ear would really bring out the unique foliage, make sure that you keep an eye on soil moisture.  This should be okay because it receives quite a lot of rainfall in the warm months in its native habitat.

Industry Value
Keep your eyes peeled for
the 'Tiny Piny' series!
The average gardener will have a difficult time finding this species if it isn't carried in their local nursery.  To learn more about the challenges and merits of growing this plant in on the industry side of horticulture, I interviewed Eddie Walsh, prominent Eucomis breeder and owner of New Zealand's Starter Plants Co.  Mr. Walsh has actually been breeding Eucomis for the past twenty years!

Although Walsh has used E. vandermerwei to create colorful hybrids, there are some challenges to nurserymen who want to grow the straight species.  "One fault we see with E. vandermerei," he explained, "is the leaves are very long and not desired by potted plant growers as they are difficult to pack and take up more bench space."  However, many of the new Eucomis hybrids that Walsh and his colleague Ian Duncalf have developed have actually been bred, in part, to address this problem.  There are some really worthwhile "minis" that have the interesting characteristics of E. vandermerwei, but are more compact for growers.

Floral display at the Hampton Court Flower Show.
One challenge to Eucomis breeders is trying to
pinpoint features that will be desirable
to consumers 9 years in the future.
Another problem is that all Eucomis species are native to the southern hemisphere.  For those who many not know, when it is summer in the northern hemisphere, it is winter in the south and vice-versa.  This means that if live plants are shipped to North America or Europe, they will struggle to adapt to our seasons.  Walsh and Duncalf handled this challenge in a really interesting way -- he sends his bulbs to India to propagate into mini-bulbs.  These new bulbs are then sent to a grower in the state of Washington who prepares them for the U.S. Market.

According to Walsh, the biggest problem with breeding pineapple lilies is that, like with many bulbs, the amount of time required. "It takes about 9 years from making a cross to having a variety ready in quantity for the market," he explained. "Who knows what colors they will want that far ahead?"

To the home gardeners reading this, keep your eyes peeled for some really adorable new "tiny piny" pineapple lilies.  Walsh informed me that the UT Gardens in Jackson are currently trialing this series, so stay tuned to their annual trials website to see how they perform in that region.  Be sure to talk to your local retail garden center or plant nursery if they don't already have these plants in stock.

If you have any questions, comments or suggestions, please feel welcome to leave a comment or send me an email.

To see more photos from this week, be sure to check out the album "If you like pineapple lilies..." on the Plante on Plants Facebook page.  "Likes", shares and comments are appreciated.

Trecanna Nursery's eye catching display of Eucomis and Crocosmia at the 2014 RHS Hampton Court Palace Flower Show.  Both of these genera are native to South Africa.


All photos and videos were taken by Amanda Plante at the Royal Botanic Gardens, Kew unless otherwise stated in the caption.

Sources:

Sunday, July 6, 2014

Add Impact (Literally) to Your Garden with the Exploding Cucumber, Ecballium elaterium

Echballium elaterium is in the
cucumber family, so it's not surprising
that the fruits look like little cukes
One this week's tasks at Kew was to prop up and cut back plants that were flopping into the grass paths of the Order Beds.  We were working under the guidance of Chrissy, one of Kew's horticulture students.  We walked through some of the lower beds, and she identified sections that needed to be propped and other plants that needed to be trimmed.  She warned me, "Watch out for the squirting cucumber."

Having just learned that one of the plants in the Cucurbitaceae beds squirted, and knowing full well what a cucumber looks like, I set off to work.  But by the time I had made my way down toward the end of the section, about twenty or so minutes later, I had already forgotten Chrissy's warning.  With the first snip of my secateurs (pruners), a small cucumber shot out from the foliage it had been hiding under and hit me square in the stomach.  Startled, I dropped my pruners and fell backwards, off of my knees and flat onto my rear.  I thought, "That's a plant worth writing about."

Mediterranean Roots
The exploding cucumber, also known as Ecballium elaterium (1790-624, UCNW), is native to the Mediterranean region.  As is true with many Mediterranean natives, this plant prefers well drained (but not dry) soil in a sunny location.  However, E. elaterium is adaptable and can handle less than ideal conditions.  Although this plant is a perennial in its native region, it is grown as an annual in cooler climates like England and much of North America (USDA hardiness zones 8b to 10a).

Flower bud, opening bloom, and
finished flower head of E. elaterium
The E. elaterium has been used medicinally since the time of the ancient Greeks.  One of the first written records of this plant is by Hippocrates (460 - 375 BC), who described how to prepare various parts of the plants to cause purging in patients.  The specific epithet elaterium is actually derived from the Greek "elaterio" which means "to cast out".  This probably has more to do with the fact that the plant shoot its seeds out up to 6 feet (see video below) rather than its medicinal use for purging and reducing fluid retention.

There is no indication that this plant is in danger of extinction in its natural habitat today, either from the CITES database or the IUCN Red List of threatened species.

Botanical Description
E. elaterium was first described in 1824 by Achille Richard, French botanist, doctor, and director of the Benjamin Delessert Herbarium and at Paris' Muséum d'Histoire Naturelle.  Several online sources state that the plant is so toxic that a doctor suffered "serious symptoms" when transporting seeds of this plant inside of his hat, from the Jardins de Plantes to his home in Paris.  Perhaps that doctor was Achille Richard?

Anatomical Characteristics
E. elaterium has the same growth habit as a bush cucumber, although the vine does not produce tendrils.  The leaves, flowers, and fruits (to an extent) also look like those of a cucumber.  However, this plant should not be eaten like a cucumber, because it is poisonous.

The exploding cucumber makes a
nice, silvery groundcover that provides
a literal impact factor to any landscape
Although the fruits looks somewhat like little cucumbers, they are much smaller (about 2 inches in length) and contain fluid and seeds.  As the fruits develop, they become slightly pinched on one side, which increases the pressure inside.  When the stem and fruits begin to yellow, a small brush from an unwary animal or gardener will cause the fruit to shoot off of its stem, spraying fluid and seeds behind it.  If any seeds get stuck to the unfortunate (and probably very startled) soul that disturbed the plant in the first place, they may transport the plant's genetic material to a new place, where the exploding cucumber can start this process all over again.

Landscape Value
The exploding cucumber has really nice silvery, densely pubescent foliage and stems.  This ground cover would be good when contrasted with plants that have different forms and textures.  Perhaps in a large container with a bold, upright 'Sparkling Burgundy' pineapple lily (Eucomis comosa) and a fine, feathery 'Rita's Gold' Boston fern (Nephrolepsis exaltata).  E. elatarium should grow to drape over the edge of the container, showcasing its beautiful foliage and explosive fruits.

This plant has a lot of impact factor -- literally.  This would be a fun addition for a home landscape near walkways to startle unwitting guests.  However, use with care.  This plant is toxic.  So although it seems like the perfect, fun addition to a children's garden, it really should not be grown in that situation.  Children may confuse the fruits with actual cucumbers, eat them, and become very sick.

So if you're looking for a fun, adaptable annual to try in your garden this year, consider adding the exploding cucumber.  Remember to plant responsibly -- this plant shouldn't be grown where children can get a hold of the fruits and eat them, because they could become very sick.

If you have any questions, comments or suggestions, please feel welcome to leave a comment or send me an email.

To see more photos from this week, be sure to check out the album "Exploding Cucumber" on the Plante on Plants Facebook page.  "Likes", shares and comments are appreciated.



All photos and videos were taken by Amanda Plante at the Royal Botanic Gardens, Kew unless otherwise stated in the caption.

Sources:

Sunday, June 29, 2014

Giants in the Conservatories, Victoria amazonica and cruziana

Introductory page to Twelve Views of
Guiana
.  Note the V. amazonica in the
water. (Schomburgk, 1841)
Several years ago when I was just getting started in horticulture, I was flipping through a textbook and saw an old photo of a child standing on a massive lily pad.  The caption read something like, "Child supported by foliage of Victoria amazonica".  I thought to myself, "I'd like to see that."  And this week I finally did.

Kew currently cultivates two species of giant waterlily, both of which are in the waterlily family Nymphaceae.  Victoria amazonica (2007-1804, KKNO), formerly V. regia, grows in the Princess of Wales Conservatory and V. cruziana (2011-1436, HSIK) in the Waterlily House.

Discovery and Present Range

According to Ray Desmond in The History of the Royal Botanic Gardens Kew, V. amazonica was first seen by a European, a botanist for the Spanish government, in 1801 in Peru. Subsequently, botanists from France spotted the species in Argentina in 1828, a Germany botanist found it in the Amazon in 1832, and Robert Schomburgk found it on the River Berbice in British Guiana in 1837.  Schomburgk shared parts of the plant that he collected and drawings with John Lindley (who had an influential role in keeping Kew intact during a turbulent period in its history).  Lindley named the plant Victoria reggia after Queen Victoria (Desmond, p. 178).

Tom and Tiffany prune and remove flower buds from
V. amazonica in the Princess of Wales Conservatory

V. cruziana inhabits a similar region, with a range from Paraguay to Northwest Argentina.  Both of these massive waterlilies can be found today in South America near Bolivia.  Neither of these species have been assessed by the IUCN for any threats to their existence in the wild.  Furthermore, CITES did not list either Victoria in their endangered species database.  Although those organizations have not listed these as threatened species, the environment they are native to could be damaged by climate change and human development.

Cultivation at Kew

Victoria amazonica was first cultivated at Kew in 1846, when twenty five seeds were bought from a collector from Bolivia.  Only two of the seeds sprouted, but they died shortly afterwards.  The issue seemed to be how the seeds were transported from Bolivia to England.  The first shipment had been packed it clay, and the next two were packed in soil in a Wardian case, dry capsules.  A fourth shipment of seeds packed in clean river water that arrived in 1849 was more successful.  That season Kew was able to raise 50 plants in a large tank in one of the glasshouses.

Visitors from around the globe stop in the
Waterlily House to inspect V. cruziana
At that time, several gardens in the area were essentially competing to see who could coax the first flower.  While the specimens at Chatsworth and Syon house were blooming, Kew's attempts were unsuccessful, possibly due to the poor quality of the Thames River water.  The first Victoria amazonica bloomed at Kew in June 1850.

The popularity of the giant water lily inspired Kew's director at the time, William Hooker, to commission a new building to house and display these finicky plants.  They completed the structure, today known as the Waterlily House, in 1852.  However, V. amazonica did not thrive, and was moved to another house (Desmond, p. 179).  Today you can find V. cruziana growing there in its place (Desmond, p. 313).

It is interesting to note that the V. cruziana growing at Kew wasn't the original collection.  Kew lost all specimens of this plant during World War II.  At that time, the conservatory at the University of Helsinki was damaged during a bombing.  Helsinki's V. cruziana survived the attack, and the progeny were sent to Kew, where they have been cultivated in the Waterlily House since 1999 (Desmond, p. 358)
Characteristics

Foliage
As is true of many plants, the foliage of Victoria unrolls as it opens.  The underside of both V. amazonica and V. cruziana is covered in sharp spines.  The prickly spines beneath the opening leaves gives a strange, otherworldly appearance to the new growth.  These spines help prevent the leaves from being eaten by hungry fish, which would negatively effect how the foliage functions.

Unfurling new growth of V. amazonica
You see, in addition to spines, there are also deep ribs underneath the massive lily pads.  These ribs hold air beneath the pad to keep it buoyant.  They also provide structural support, like the frame of a house.  Enough strength, at times, to support the weight of a small human.  So if a grazing fish were to nibble too much of the foliage, this would compromise the strength of the leaf and its ability to stay afloat.

Another interesting fact about Victoria leaves is that the foliage will grow to the size of the container.  When I asked Silke, who works in the Waterlily house about the feasibility for growing V. cruziana at home, she concluded that it would be possible, but difficult.  And if placed in the size pond that is regularly found in a home landscape, the foliage wouldn't be much larger than that of any other lily pad.

Differences
Although the leaves of V. cruziana
(above) are smaller than V. amazonica,
it has a much taller lip.
So what's the difference between the foliage of these two giants?  For one thing, V. amazonica tends to produce larger leaves.  The foliage of V. amazonica can reach 2.5 meters in diameter, while the diameter of V. cruziana's leaves usually maxes out closer to 2 meters.  But these statistics don't stop a little friendly competition between staff in the Waterlily House and the Princess of Wales Conservatory. 

This year, the staff competed to see who could produce the largest lily pad by a certain date. Silke in the Waterlily house told me that her group had lost the competition because they got a later start.  I asked Tom, an apprentice, and Tiffany, a staff member, in the Princess of Wales Conservatory about the wager.  Tom grinned and said, "Yeah, it wasn't even close."

Although the foliage of V. amazonica may grow larger than V. cruziana, the edge of the pad is not as tall.  While this may not seem that important at first, a tall edge is crucial to prevent other leaves that would compete for sunlight from sliding on top of the pad.  This lip can also be more aesthetically appealing.  It provides more of a reflection on the water, and is really lovely when the sunlight shines through.

Flower
Unopened V. amazonica flower bud, held by Tom, an
apprentice in Kew's Princess of Wales Conservatory
Both species have large, creamy white flowers that open in the evening and are pollinated by beetles. Even though both giant waterlilies are starting to set flower buds at Kew, you won't see any on display until later in the year.  When I arrived at the Princess of Wales Conservatory, Tiffany and Tom were pruning out the prickly buds to compost.  The reason why is that if allowed to flower, the plants' energy would go into flowering, fruiting, and setting seed rather than growing large leaves.  People come to Kew from all around the world to see these massive lily pads, so Kew does their best to produce big ones.

However, the species in cultivation at Kew are allowed to flower later in the year, because the seed is vital to producing the next season's crop.  Neither V. amazonica or V. cruziana will reliably overwinter at Kew, even if provided the best possible environment.  So, staff pollinate the flowers by hand, store the seeds in water, and start new seedlings early in the year and grow them on in the Tropical Nursery glasshouse so when they are ready to move they are large and ready for visitors.

Cultivation

Tom disects the unopened flower bud
of V. amazonica so we can inspect
the anatomical features
Although both species of Victoria thrive at Kew during the warmer months, both begin to decline in the fall.  This makes sense, because both plants are native to the tropics of South America.  For interested readers in the US, their USDA Hardiness Zones are 10-11.  For readers in the UK and beyond, that means they can tolerate a minimum temperature somewhere between 4 and 11 degrees Celsius.  Measures could be taken to overwinter the plants, but the effort would require very specialized environments with specific heat, supplemental light, and water requirements.  Instead, Kew treats these plants as annuals rather than temperennials.

In Kew's online profile of V. amazonica, they note that aphids can be a problem at times.  They try to reduce pest and disease pressures by keeping the plants healthy and happy by adding plenty of fertilizer, growing in a large enough pot, and regular pruning.

A Sight Worth Seeing

Before leaving the Princess of Wales Conservatory, I took a moment to stand back and take in one last look of those giant leaves.  An older gentleman had pushed his father in a wheelchair to the water's edge while I'd been speaking to Tiffany and Tom.  "What do you think of it?" I asked.  "I've never seen anything like it," the father responded. "Neither have I."
If you have any questions, comments or suggestions, please feel welcome to leave a comment or send me an email.

Victoria amazonica can be seen in Kew's Princess of Wales Conservatory
Kew's Victoria cruziana is on display in the Waterlily House
All photos were taken by Amanda Plante at the Royal Botanic Gardens, Kew unless otherwise stated in the caption.

Sources:
  • Center for the International Trade in Endangered Species database
  • Desmond, Ray.  (2007).  The History of the Royal Botanic Gardens Kew (2nd Edition).  London: Kew Publishing, Royal Botanic Gardens, Kew.  177-179, 345-346.
  • Kew's Living Collections database
  • Missouri Botanic Gardens plant finder database
  • Perennial Resource glossary
  • The International Union for Conservation of Nature and Natural Resources Red List of threatened species
  • The Plant List website
  • The Royal Botanic Gardens, Kew website and staff
  • Schomburgk, Robert H. (1841).  Twelve views in the interior of Guiana from drawings executed by Mr. Charles Bentley, after sketches taken during the expedition carrier on in the years 1835 to 1839, under the direction of the Royal Geographical Society of London, and aided by Her Majesty's government with descriptive letter-press.  Retrieved from The New York Botanical Garden Mertz Digital Collections.

Saturday, March 15, 2014

Looking for Spring Color? Go for a Native Maple

Native maples in their fall glory in GSMNP.
In addition to their fall foliage, maples should
be valued for their early spring blooms.

I love spring!  Signs of life, like buds forming on a tree or sprays of flowers pushing from the cold soil, make me think of the earth yawning, stretching, and rubbing the sleep from its eyes, ready to wake up for another season of growth.  One of my favorite signs of spring is when our native maples (Acer rubrum, A. saccharum, A. saccharinum) begin to bloom.

When many of us think of maples, our minds probably go straight to their spectacular fall foliage.  This is why most of the North American maples in the nursery industry are bred for their autumn color.  Their delicate spring blossoms are often overlooked, but en masse maples in flower can be real show stoppers.

My favorite way to view maples in their spring glory is by taking a long, Sunday drive on a back road.  Last weekend we drove down Route 441 from Townsend, Tennessee to Lake City, Florida.  The whole way down our native maples painted the roadside with sunny limes, yellows, peachy pinks, and bold scarlet reds.  Over the next month, whole mountain sides in the Great Smoky Mountains National Park will be dotted with the colors of maples in bloom. 

A cluster of maple inflorescences
Some specimens produce bolder, showier blooms than others.  Maples can bloom as early as January or as late as April.  Flowering in maples is both a response to environmental conditions and a function of genetic predisposition.  Genetic variation is responsible for inconsistency in blooming, which causes stands of maples in the wild to produce a smattering of blooms throughout the spring.  Although nursery breeders seek to control the genetic qualities of the maples they produce, flower time and quality is often an afterthought.  This means that maple flowering in the landscape can be just as inconsistent between two plants as in the wild.

When in flower, our North American native
maples can be just as showy as many
of the more familiar spring blooming trees

Unlike other spring flowering trees that are pollinated by bees and other insects (such as cherries, dogwoods, and redbuds) maples are wind pollinated. The earlier maples are able to blossom, the fewer barriers there will be to pollination.  For example, if a maple flowers in January, none of the other trees or shrubs have leafed out yet, so the pollen can travel unhindered from one flower to another.  This can be a risky move, because a cold snap can damage flowers and samara development.  On the other hand, if a maple flowers in April there will be less danger of cold damage. However, many other trees in the landscape may already have foliage, preventing how effectively wind can carry the pollen between flowers. 

Those who want to enjoy the spring blossoms of maples in the comfort of their own landscape may be in for disappointment.  As stated earlier, the industry doesn't currently breed maples for flower quality.  Strong, handsome maples that provide beauty, shade, and vibrant fall color may also produce lackluster blooms.  However, there are a few things you can do to improve your odds of finding a maple that will add stunning spring blooms to your landscape:

  • Consider a red maple (Acer rubrum) - Red maples purchased from a reputable nursery don't just produce red fall foliage (although many may also have yellow, green, and orange fall color).  Red maples tend to also generate scarlet inflorescences.  To quote Dr. Michael Dirr in his Manual of Woody Landscape Plants (1998), A. rubrum's "red, rarely yellowish" spring blooms may be composed of mostly pistils, stamins, or they may be monoecous, but "all are showy".
  • Buy local - This tip doesn't just mean you should support your local garden centers (which is always a good thing to do!).  Maples grown in your area are more likely to perform well in the long term and endure in the landscape than maples grown in another region of the country.  This is especially true for folks up north -- although maples grown in the south may be the same species as the maples native to your area, they typically aren't as cold hardy.
  • Avoid grafts? - If you're looking for a Japanese maple (A. palmatum), a graft is a must.  However, there are mixed reviews of how grafted red maples perform in the long run.  Dirr (1998) noted that grafted native maples tend to not perform as well long-term as maples grown from cuttings, tissue culture, or seed.  Remember, seed-grown plants may last longer than a maple grown from a graft, but with the genetic variation of seed-grown plants you never know what you're going to get.  On the other hand, Matt Nichols of Mr. Maple has successfully grafted red maples and has grafted sugar maples.  It would be a good idea to do some investigating and buy from a quality nursery.

Thank you to Garden Talk on Knox Talk 94.3 FM for inviting me on to present their plant of the week this morning!  If you're wondering, the featured plant was Acer rubrum.  To read more of my favorite plants, be sure to follow me on Plante on Plants.  To tune in to more gab from the garden gurus, stream Garden Talk live online on the Knox Talk website.

If you have any questions, ideas or suggestions, please feel welcome to post a comment below or to send me an email.

What are some plants that shout SPRING to you?  What's your experience with our native maples?  What are some other overlooked spring bloomers?


The delicate flower buds of Acer rubrum
Acer rubrum in bloom
A hybrid maple, Acer x freemanii, makes an attractive street tree on the University of Tennessee's Agriculture campus.

Friday, November 1, 2013

Candy Corn Plant

The blooms of Candy Corn Plant resemble the staple
Halloween candy "candy corn"
It's officially halloween weekend, and I can't think of a more fitting plant to write about than Cuphea micropetala, commonly known as candy corn plant.  The common name is derived from the fact that the fall blooms closely resemble the staple halloween candy "candy corn".  In Knoxville, this Cuphea is at the height of flowering the week of the haunted holiday.

Candy corn plant is a hardy annual / tender perennial in zones (7)8-10, and is grown as an annual in cooler climates.  The glossy green foliage is evergreen in areas where this plant returns perennially.  Site in full sun for best performance.  Candy corn plant prefers moist but well drained soil.  In Knoxville, I haven't seen this plant get much larger than 3 feet tall and 3 feet wide.  I've read that 'David Verity' is a good selection, but haven't seen it in cultivation.

The showy blooms aren't just attractive to gardeners -- butterflies and hummingbirds find the flowers irresistible as a source of nectar.  As a student intern at the University of Tennessee Gardens perennial border, I once watched several hummingbirds wage full out battle over who had the rights to our specimen of C. micropetala.  In my experience, sulfur type butterflies seem to prefer this plant as a food source more than the showy swallowtails or monarchs.

C. micropetala is an underused plant, especially in my region of the country.  I've only seen this plant in a handful of gardens, and only as a single specimen.  I'd love to see this plant en masse in a variety of landscape situations.  If you're in zones (7)8-10, right now or later in April would be a great time to plant candy corn plant.  For folks who garden in a cooler climate, wait until spring when the danger of frost has passed.

The photos for this blog are courtesy of the undergraduate teaching assistants for UT's course Plant Sciences 220: Landscape Plant ID I.  They upload tons of wonderful photos as a study aid to the class Facebook page.  The photographer was TA Austin H.

If you have any questions, ideas or suggestions, please feel welcome to post a comment below or to send me an email.

What are some other good plants for a halloween themed garden?

What's your experience growing candy corn plant?  How has this plant performed in your garden?


Mature selection of Candy Corn Plant from the UT Gardens

Thursday, August 1, 2013

Illuminate Your Landscape with Golden Boston Fern

The chartreuse foliage of this variety of
Boston fern illuminates a shady situation
at the UT Gardens in Knoxville.
As an apartment dweller, my landscape is limited to window boxes, patio plants, hanging baskets, and interior plants.  My favorite annual landscape plant this year has been the golden Boston fern.  The fine, chartreuse foliage of this Nephrolepis exaltata has illuminated my shady porch in a way that a typical green Boston fern just can't.

A Multitude of Uses

  • This variety of fern has thrived in a container on my patio, a hanging basket, and even indoors in my tabletop aquaponic system.  
  • In the past, the golden Boston fern has grown excellently in a couple of living wall systems that we demonstrated at the Southeastern Flower Show.  
  • This variety of fern performs really well in a summery mixed container.  Partner with pink flowers or purple foliage for a color combination that really pops.  Mixing with the bold texture of a Caladium or a shade tolerant elephant ear will make this plant's feathery foliage stand out.
  • My favorite use of this versatile tropical is as an annual in the shade garden.  The brilliant foliage really shines a little light in a shady situation.  
A sprig of this golden Boston fern has really
taken to life in my home aquaponic system.
Preferred Conditions

Golden Boston fern prefers dappled shade.  Full sun will burn this fern's sensitive foliage.  Keep soil moist but well drained for best growth.  This tropical annual won't overwinter in anything less than USDA Hardiness Zone 10a.  Your local garden center or plant nursery should carry this variety of fern.  If they don't, I'm sure they'll be happy to order it for you.  You can also order by mail from Randolph's Greenhouses

Origin

The chartreuse variety of Boston fern was first discovered by Jason Reeves, the curator at the University of Tennessee trial gardens in Jackson, TN.  Rita Randolph of Randolph's Greenhouses shared the plant with Allan Armitage, former director of the University of Georgia Trial Gardens in Athens.  Armitage named the plant 'Rita's Gold', and the variety went on to win the Classic City Award for its performance in the landscape.  

I've pieced together the humble beginnings of this particular fern based on conversations with horticultural experts and online research.  Please don't hesitate to shoot me an email if there's anything that should be added or modified.

To see more of my photos of the versatile golden Boston fern, be sure to check out my flickr set.

If you have any questions, ideas or suggestions, please leave a comment below or shoot me an email.

How has this golden Boston fern grown for you?  What tropical annuals have thrived in your garden this summer?  What plants do you use to illuminate your landscape?

Splashes of gold brighten two of the interior living walls highlighted at the Southeastern Flower Show in Atlanta, GA and the Dogwood Arts Home and Garden Show in Knoxville, TN