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.

 A bit after posting this plant profile, my new friend Ann in Australia sent some helpful information that I wanted to be sure to share with you.  Thanks for sharing Ann!

"I live in the Lower Blue Mountains west of Sydney, New South Wales, Australia.  We have very hot, dry but humid summers. (Heat zone 4, cold zone 10). Recently up to 46 C. I planted my Romneya about 10 years ago in my front garden,  in a dry westerly aspect  in full sun, on a slope with good drainage. It is tall (about 2 to 2.5metres high) with lanky canes and flowers on new growth which I cut back in late autumn to about 15cm. It will sucker by sending out underground rhizomes several metres away  and also sets seed once the plant is established. It has beautiful crepe paper thin wrinkled petals of pure white & a large raised centre of golden stamens heavily laden with pollen. The flowers measure roughly 15cm and the foliage is a smooth blue/grey. I don’t fertilise it & it relies solely on natural rainfall. The flowers are a constant delight to the bees and the shrub often “hums” with bee activity. People will often stop and ask me what this beautiful plant is when in flower."

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

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:

• "Richard, Achille (1794 - 1852)".  JSTOR Plant Lives.
• Center for the International Trade in Endangered Species database
• Dave's Garden Plant Files
• Eland, Sue.  (2008).  "Ecballium elaterium." Plant biographies: A bird's eye view of the planet and man.
• Grieve, M.  "Cucumber, Squirting".  Botanical.com: A modern herbal.
• Kew's Living Collections database
• 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

Quick and Dirty Tips for Tree Planting

I apologize for falling behind on blogging.  School this semester has not left a lot of free time for writing, but I do want to continue with regular posts.  So, in the spirit of brevity, please enjoy the following quick and dirty tips for planting trees.  Stay tuned for the quick and dirty tips for pruning.

Timing is Everything
Cool winter months is a great time to plant dormant trees and shrubs.  Without the burden of green foliage that requires a constant flow of water, woody specimens are able to develop a healthy root system.  The earlier in the winter that you plant your trees, the more time their roots have to develop, and the better prepared the trees are to withstand summer heat.  In Knoxville, March is about the latest that I would recommend planting trees and shrubs.

A "bare root" tree is exactly what it sounds
like -- there is not soil around the roots.

Container or Bare-Root?
Many homeowners buy trees and shrubs grown in containers from a nursery or box store.  While I am all for supporting your local nursery, I prefer to plant "bare root" woody specimens.  Bare root plants are exactly what they sound like -- there is no soil around their roots.  In my experience, bare root trees and shrubs are less expensive, establish faster and perform better than container grown plants.  Bare root specimens can be ordered through the internet or catalogue from a reputable source.  Ball and burlap is another option as well.

Eliminate the Competition
Although most weeds in and of themselves may not be a threat to successful growth of trees and shrubs, their presence near the trunk is undesirable for a couple reasons.  Aesthetically, you may not want weeds cluttering up the "drip zone," or area beneath the foliage of your tree.  If the tree is to be planted in an area that is mowed regularly -- like the front yard -- if there are weeds and grass growing near the trunk you may risk having your tree damaged by a weed eater or lawn mower.  For these reasons, it is a good idea to use your shovel to remove existing weeds and grass from the area around your tree prior to planting.

Make sure your hole is at least big enough
to hold all of the plant's roots.

Dig Baby, Dig
If your tree is a container tree, make sure your hole is at least bigger than the plant's container.  Some people suggest digging a hole that is twice as wide.  I haven't noticed much of a short or long term difference between the growth of trees that were planted in sufficient size and larger holes.  If you are planting a bare root tree or shrub, make sure the hole is large enough to sufficiently hold all the roots.

To Amend or Not to Amend
Some people amend the soil in the hole with potting soil, good topsoil, sand, compost, or fertilizer.  I like to think of it this way -- in a year, your tree's roots are going to expand far beyond that zone.  Why put off the inevitable?  In some cases, amending the soil can actually hurt the tree's development.  For example, if a heavy clay soil is amended for a tree, the slow draining clay can create a basin that holds water around the tree's roots and causes them to rot.  However, if you are growing a tree or shrub that has a specific soil pH (acidity or alkalinity) requirement, the soil will need to be amended with sulfur to lower pH and make more acidic or lime to raise pH and make more alkaline in order for the tree to grow properly.

Look for the "root / shoot" junction before
planting your tree.

Look for the Root-Shoot Junction
There have been times when I've planted a tree and a year later it dies inexplicably.  My sleuthing did not turn up any fatal pest or disease problems.  The cause of the tree death was actually being planted too low or too high.  Now when I plant trees, I keep my eyes peeled for something called the "root / shoot junction."  Look on the trunk of your tree for the spot where the roots become the roots and the shoot becomes the shoot.  When you plant your tree, make sure the roots are below ground and the trunk is above ground.  Most of the time, the soil line of container grown trees is already at the root / shoot junction, but double check to be sure.

Add Mulch
Mulch is important for weed suppression, protecting the trees from lawn mower or weed eater damage, and just plain old looks pretty.  For new beds, add about 3 inches of mulch under the drip zone of the tree.  After mulching, be sure to pull the mulch away from the trunk of the tree.  Be sure to avoid the "mulch volcano" look -- that is not attractive and it is unhealthy for your tree.

Thanks for reading and stay tuned for the quick and dirty tips for pruning, hopefully coming up soon!

If you have any questions, ideas, or comments, please don't hesitate to leave a comment or send me an email.

To see more of my tree maintenance pictures, check out my photobucket story.

Do you prefer container trees or bare-root?  What tips and tricks have made your trees and shrubs grow successfully?

The Knoxville Botanical Garden and Arboretum's "Every Child Outdoors" Fruit Grove

Tomatoes in December? Grow the Gift of an Edible Ornament

I love the holidays.  Every December I look forward to all the Christmas trees, wreaths, cookies and ornaments   But holiday traditions don't have to be so... traditional.  If you want to give a gift with WOW factor this year, consider the 'Sweet n' Neat' tomato.

'Sweet n' Neat' Tomatoes make a
lovely, living edible ornament

'Sweet n' Neat' tomatoes are a compact variety that is content to grow on a sunny windowsill.  These edible ornaments will brighten any home or office with small red, scarlet, or yellow cherry tomatoes -- even during the winter.  Pot size isn't a major issue for 'Sweet n' Neat' -- I've heard of instances where this variety has developed fruit while still growing in the small nursery cell pack weeks before a sale.

I first heard of this variety while attending the Perennial Plant Association's 2012 symposium.  In the talk "Food for Thought, Edibles in the Landscape," Lloyd Traven of Peace Tree Farm shared his edible ornament idea with the audience, and he suggested 'Sweet n' Neat' as a good variety for the concept.

Working with Knoxville's Austin-East High School, we grew 200 edible ornaments as a fundraiser for their garden program.  There was immediate and intense interest!  This has been a very popular concept for a plant sale, and I'd definitely recommend other schools that have access to a greenhouse try this in the future.

A rosemary tree is another edible
and living holiday gift idea.

If you're looking for some seed for your home garden, there are many websites that offer yellow, red, and scarlet fruiting 'Sweet n' Neat' tomato seeds.  If you intend to grow the plants for a fundraiser, there aren't many retailers that currently sell this variety in bulk.  However, 2B Seeds does sell all three colors of 'Sweet n' Neat' in quantities of 100.

This variety may not be available from a big box store, but check with your local garden center to see if they carry any.  If not, suggest they grow some for the next holiday season!  Knoxvillians can pick up their edible ornaments by contacting myself or the lead teacher of Austin-East High School's garden program.

A rosemary tree makes another lively holiday gift.  Consider purchasing from a good local nursery instead of the grocery store or a big box store.  Rosemary grown at a local nursery is more likely to have been properly cared for and will make a more healthy gift.  In my experience, grocery chains and box stores tend to over-water their rosemary trees, which can result in an algae-ridden, smelly plant that has root rot (and who would want that?).  Be sure to inform recipients that their rosemary probably won't be hardy enough for life outdoors, and will enjoy spending chilly winters inside or in the garage.

Add a festive, living gift to your holiday traditions.  The gardeners on your Christmas list will be glad you did!

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

How do you incorporate gardening into your holiday traditions?  What are your experiences with growing 'Sweet n' Neat' Tomatoes or rosemary trees?

Gardeners fight the winter blues with fiery red twig dogwoods

Red twig dogwoods add a splash of
color to the winter landscape

Winter is the season when the garden sleeps. Green turns to brown and flowers fade. Embracing the season of dormancy doesn't have to mean acceptance of a dreary landscape. Add a splash of color to the winter garden with red and yellow twig dogwoods that are most exciting in dormancy.

Strategically placed, colorful twig dogwoods help break the monotony of evergreen foundation plantings.  Although twig dogwoods are attractive as a specimen plant, they really make a statement en masse.  Plant at the border to create a river of color as a winter hedge.

Of all the interesting new varieties out there, my favorite is Cornus alba 'Ivory Halo' (zones 3-7).  While other twig dogwoods tend to be a blob of green during the growing season, variegated foliage makes 'Ivory Halo' an attractive planting for any time of year.

Young dormant stems of 'Ivory Halo' are a fiery red that are an excellent source of winter interest.  For the best stem color, prune out old growth every spring or cut back hard the whole plant every few years.

Variegated foliage makes 'Ivory Halo'
dogwood attractive at any time of year.

Plant dogwoods in the winter when the plant is dormant.  Although dogwoods won't be actively growing leaves and stems in the winter months, roots will anchor into the soil and give the plant a head start on growth in the spring.

Available from many garden centers, a red or yellow twig dogwood will make the perfect holiday gift for any garden enthusiast.

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

What's your favorite way to use red or yellow twig dogwoods?  What plants are your favorites for fighting the winter blues?

Fiery stems of red twig dogwoods contrast with white bark of paper birches (Betula papyrifera)

Yellow twig dogwood at the University of Tennessee Gardens.

Photos courtesy of:

• Missouri Botanical Garden
• The Gardeners Eden
• The Tough Love Gardener
• University of Tennessee Garden

Verbena 'Homestead Purple'

Butterflies, like this swallowtail,
absolutely love 'Homestead Purple' verbena

Verbena canadensis, also known as "Clump Verbena", is valued for its color, habit, and durability. Round clusters of flowers on all clumping verbenas generally last from summer until fall, contrasting the almost spherical flower-shape with the very prostrate habit of the plant itself. Reaching 9" in height at the most, this plant can be a vigorous spreader. In fact, Clump Verbena propagates itself easily by air-layering. That is, its stems grow so low to the ground, that given the right conditions the stems will start to grow new roots and spread even farther as a new plant. This plant does best in a well-drained soil and a full-sun site, but keep in mind that when this plant is happy, it can become incredibly difficult to manage because it will spread so vigorously. If planted in perhaps partial-sun, the plant should live but be less vigorous and produce fewer flowers. Also, if planted in soil that does not drain well, Clump Verbena becomes susceptible to powdery mildew. Be aware of what hardiness zone you are in when planting Clump Verbena, because it is only hardy as a perennial in zones 6 - 10. If planted any farther north from our East Tennessee location, Clump Verbena is considered an annual.

The story of Verbena canadensis 'Homestead Purple' is one worth mentioning. It begins when two horticulturalists from the University of Georgia by the names of Allan Armitage and Michael Dirr (sound familiar?  You may see these names on your book shelf) were driving back to their university from Atlanta, GA. At one point, a brilliant purple in a yard they were passing happened to catch their eyes. They went to investigate what particular variety it was, but the homeowner only knew that it had always been growing in her yard. She gave them some cuttings which were later named 'Homestead Purple'. Today it is believed that 'Homestead Purple' is a cross between the traditional Verbena canadensis and some unknown variety that may not even exist anymore.

The cultivar of Verbena canadensis 'Homestead Purple' is valued in today's market for its low spreading habit, rich purple flowers, and spring / early summer blooms that will last until frost. This specific cultivar is located in at least three areas of the University of Tennessee Gardens. Not only is 'Homestead Purple' valued for its long bloom period, but the coarse texture of its evergreen foliage can definitely add winter interest to your perennial garden. Also, if you want to attract wildlife such as butterflies, this plant is an excellent selection. One suggestion for 'Homestead Purple' is that it should be planted near taller, more shrubby plants. This way, if it grows vigorously, it will not suffocate other smaller plants and you won't have to worry about cutting it back so often.

Update (2013): 'Homestead Purple' is easily propagated by rooting cuttings, division, or just pulling up stem sections that have rooted by layering.  March of last year we planted 3 very small rooted cuttings of 'Homestead Purple' around the Knoxville Botanical Garden & Arboretum's new "Every Child Outdoors" Youth Vegetable Garden.  Each plant was just around 3 inches tall.  By May, each plant was so large many visitors believed the Verbana that were spilling out of the beds must have been there for years (We had only just built the garden!).

'Homestead Purple' is an impressive, reliable perennial that can't be beat in a "transition zone" garden.



Sources
North Creek Nurseries
Stills, Steven M. Manual of Herbaceous Ornamental Plants.

Photo from: http://www.allanarmitage.net/about_dr_armitage