Dumbarton Oaks Art Installation

It's pathetic how many photos I have of Dumbarton Oaks in the fall and winter, and how few I have of the spring.  I suppose it's indicative of how busy folks in my field are each spring.  But yesterday, for Easter, I actually took the afternoon to enjoy a visit.  

Perhaps the most lovely surprise was the new art installation, Cloud Terrace, by Andy Cao and Xavier Perrot.  It's placed on the Arbor Terrace and composed of chicken wire and Swarovski "Elements" (according to the info sheet the Gardens' provided).

On such a bright sunny day, seeing the dense gray "clouds" of the wire made a marked contrast.  But sadly, photos don't accurately capture the dazzling rainbow of colors reflected by the crystals, which are tethered to the wire.

The black reflection in the pool highlights some of the ruby and sapphire hues that were twinkling when a breeze lifted, but photos don't do it justice.  Definitely check it out between now and autumn!

The Senator Falls

So, those of you who are up to speed on your big tree news may already know this -- but one of the world's largest trees collapsed in flames last weekend.  It was one of those news oddities that got picked up on morning radio stations and when I heard the story, you can imagine I went straight to the interwebs to investigate more.  

'The Senator' as the tree was lovingly nicknamed, was a baldcypress growing in Longwood, Florida.  Today I was on the National Mall and snapped a few shots of The Senator's genetic cousin, Taxodium ascendens. Baldcypresses can be the East Coast's largest trees and The Senator was designated in 2006 as the largest tree (of any species) east of the Mississippi.  It was estimated to be about 3,500 years old, ranking it as the fifth oldest tree in the world.  

While this species on the mall is probably about 50-65' high, The Senator was 165' high until 1929 when a hurricane topped it.  Shortly before its demise the plant stood at about 125' - just 25' shy of the Statue of Liberty.  The diameter of the trunk measured at just over 17'.  That's probably about 5-6 times bigger than the tree in these photos.  Those dimensions are quoted in this article, though it should be noted that arson is no longer being considered as a source of the fire that ultimately felled the tree.  

Balcypresses are given their name since they are deciduous cypresses, losing their leaves in the winter, which is a rare occurrence for a gymnosperm (i.e. non flowering plant).  The habit is upright and conical.  The plants thrive in swamps and saturated conditions.  It's this tolerance to anaerobic conditions that have lead to its more frequent use as street trees (since the conditions under concrete sidewalks are similarly limited in oxygen).

Early Winter Textures

I was in Tenleytown in DC the other day and was struck by the combination of textures in this relatively ordinary urban garden. Unfortunately I only had my iPhone 3GS, which is beginning to feel the effects of 2 years of abuse (well...Not quite 2 years -- my contract is up in March at which point I can get a new phone at a discount!).

In any case, the Spirea thunbergii looks beautiful in autumn and it's easy to forget what lovely fall color it has.  The toasted honey hue looks perfect with the grasses flanking it on both sides.

As much as I love the look now, I'm not sure I'd ever combine S. thunbergii with grasses due to the way they'd look in spring or summer -- I'm not sure I'd buy that they'd look good together.  But I'll have to keep an eye on this garden come spring to reconsider.

Epimedium

I can't believe I have not blogged about Epimedium since May 2008.  I felt for sure I had touched on this plant since starting Planted Cloud.  In any case, I was in Dumbarton Oaks a few weeks ago and was struck once again at how lovely the fall color is on this herbaceous groundcover.

Back in 2008, I did touch on the medicinal history for Epimedium -- the common name is barrenwort, and it was presumed that ingesting this would help with impotence, thus solving the 'condition' of barrenness.

I'm not naming a species here, as there are over 60 in cultivation.  Most commonly however would be E. x rubrum.  Below is one such species in the spring.  You can see how strikingly different even the greens are among these two specimens in spring and fall.  Regardless of species, Epimedium usually has chartreuse new leaves that are somewhat soft in texture.  By autumn, the leaves become more leathery and darker green.

Lindera benzoin

Here's another plant from my class last Saturday: Lindera benzoin or spicebush.  Spicebush is a plant that can easily be missed during the summer and winter, but during spring, when it's in bloom, and fall, when it shows off its amazing fall color, you cannot miss it. 

The fall color is a clear honey yellow on large ovate leaves with entire margins.  The leaves themselves could be confused with other plants, but it's easy enough to confirm that you are looking at Lindera by crushing and smelling the leaves.  They will emit a spicy, lemony scent.  Thus the name spicebush.  The twigs and fruits are equally fragrant.

This specimen must be a male, as otherwise, we'd likely see the red berries that typically appear in late summer/early fall.  Instead, we can only see the flower buds for next spring.  The plant is an important species for survival of the spicebush swallowtail, which lays eggs on the plant.

Spicebush has a long history of medicinal uses by Native Americans and is now available commercially for homeopathic uses.  The leaves, when crushed, can be used as a poultice for burns or cuts.  The plant can also be used for flavoring food and for making a tea.  Lindera is derivative from from the botanist Lindler; benzoin is derivative of the Middle French word 'benjoin' which means 'Java Frankincense' and referring to the spicy aroma of the plant.

Muhlenbergia capillaris

Muhlenbergia capillaris, or muhly grass, is one of my favorite ornamental grasses.  It's compact, reaching a non-flowering height of 36" (which makes it more convenient than a plus size Panicum virgatum in smaller residential settings) but most striking are the purplish red blooms that appear each autumn.

Recently, I specified the plant on a contemporary modern home that had a perimeter fence made of 66" high Corten steel sheeting.  The house itself had a pure white stucco facade and I placed the muhly grass along the base of the structure, mirroring (on a conceptual level, at least) the deep rust of the Corten. 

I've been very happy with the results and as soon as I get some decent finished installation, I will place them on my firm's website.  But for now, in case you've noticed the lovely gem and wondered what it was, I thought I'd share these pics from Bartholdi Gardens in DC.

Celtis occidentalis

How in the world is it that I haven't yet blogged about hackberry, or Celtis occidentalis? While it's not a particularly great ornamental tree, this native is common in the mid-Atlantic and is an outstanding plant for creating butterfly habitat.  

Everyone knows that butterflies gather nectar from tubular flowers, so when I write about butterfly habitat, I'm speaking more about the habitat it provides for caterpillars and eggs, which is obvioulsy equally important.

I tell students that the bark of hackberry, which is very distinctive, looks like gray molding clay that someone has hacked up with a fork or knife.  But that's not at all why the common name exists.  Instead, it's derivative of the Scottish name 'hagberry' which is actually in reference to a cherry (Prunus) species. 

The word Celtis is derivative of ancient Greek for a tree with sweet fruit, and while there are berries on hackberry, I would leave them for the birds (and caterpillars).  Occidentalis means 'western' which can cause initial confusion for us folks on the east coast.  But in botanical nomenclature, western means the new world, not the west coast of the new world.

The specimen above is at the Smithsonian's Butterfly Habitat Garden, though the top photos are from Central Park.  The plant is prevalent in both locations, though one also regularly encounters C. laevigata or sugarberry.

Mystery....Euphorbia?

My students and I encountered this plant at the Museum of the American Indian last week.  Damn, if I'm not stumped on what it is.  Any ideas?

At first glance, I thought it may be an Aslcepias, primarily because it looked like milkweed bugs were on the stem. But after reviewing this old post, I'm pretty sure they aren't milkweed bugs and certain this isn't an Asclepias (though the stem, when broken, did emit a milky glaze). 

The overall habit reminds me of an Euphobia, though I can't confirm a particular species.  The jointed stems also have me a bit stumped. Whataever it is, I love the variable fall color, with orangey green hues along the center, turning deep burgundy at the leaves' edges.

Okra

The other day, my DC students and I were suffering the recent cold snap of weather, touring gardens around the mall, in search of some notable fall plants.  We found this at a community garden nearby.  At first glance, the leaves (and most of all the flowers) indicate the plant is in the Malvaceae (hibiscus) family, and luckily one of my students instantly recognized this as okra, or Abelmoschus esculentus.

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Below, you can look inside the flower and see why it's so clearly a hibiscus type plant -- the sexual parts of the flower are arranged in along a staminal column - a tall sheath encloses the stems of the pistil, which emerge at the top of the column (the velvety black parts below).  Along the column, stamens and anthers extend, perpendicular to the length of the column. 

At the bottom left on both photos you can see the remaining seed pod after flowering is complete.  The pod is the actual okra forming.  Okra is distinctive by its octagonal cross section.  It's common in southern US food as well as in recipes in the middle east and southeast Asia.  Most of the recipes include stir frying or flash cooking the whole pods.  If they are slow cooked, they become a bit slimy, as the skin that breaks down in heat is mucilaginous. Slicing the pods is common in cajun food like gumbo, and in this case, any broken down 'goo' is cooked off in the soupy mix. 

Depending on the cultivars, some okras are hardy in this zone.  Typically however they are annual.

Dutch Elm Disease

The fourth blog post I ever wrote featured the American elm (Ulmus americana). And that seems totally appropriate, as the American elm is probably one of the most exquisitely beautiful trees that we can claim as our own.  Most prevalent along the riverbeds in the midwest, the tree has lovely golden-orange fall color, large ovate, toothed leaves (with asymmetrical leaf bases) and beautifully fissured bark on branches which elegantly spread into a v-shaped canopy. 

Sadly, too often any remaining specimens left -- especially those in the wild -- look like this, or worse.  That's because since the 1960's the population of American elms has been decimated by Dutch elm disease, or various species of the fungus Ophiostoma. The vector (or carrier) for this pathogen is the elm beetle, which first emigrated to the United States via a delivery of Dutch logs shipped to Ohio to use as veneer for furniture.  The beetle burrows into the bark of the elm to lay eggs.  While borers like this can damage trees simply by this process, more dramatic is the resulting infection of the fungal pathogen.  Even in areas where no beetles are present, one infected tree can pass on the fungus to a neighbor if the roots graft underground. 

The tree's defense against this infection is to essentially close up shop; the canals of xylem and phloem close, blocking further spread of the disease.  Unfortunately, at this point damage has been done and the tree slowly dies back.  These photos well demonstrate the appearance of an untreated American elm. Ironically enough, European elms such as the English elm (Ulmus procera) are equally devastated by the disease and first contracted it in a shipment of American timber. (See Wiki for more.)

Land management strategies in some wild populations of elms and the famous allees in Central Park and along the National Mall keep the disease at bay. Frankly, I'm surprised these two trees (near the Yards Park in DC) have remained standing.

Euphorbia amygdaloides var. robbiae

Last night was my first day of class back at the program in DC -- this semester I'm teaching a perennials for fall course, which I suspect will include no shortage of wonderful grasses and ferns.  

In the meantime, we did take a look at this handy groundcover -- Euphorbia amygdaloides var. robbiae.  The common name, besides Robb's Euphorbia, can also be wood spurge, which led to some confusion last night, since that is also a name for the native Pachysandra, P. procumbens.. Add to that, this plant is similar(ish) to Pachysandra, in that it's an evergreen groundcover that spreads easily and quickly.

Of course, the radial leaf arrangement (the almond shape of the leaf accounts for the species name amygdaloides which means almond-like) is quite different and this plant has tall spikes of yellow flowers in the spring.  The flowers (which are most noticeable due to their showy bracts and involucres) persist for several weeks in the spring.

Stewartia ovata

This was an exciting new find for me at Kenilworth --  Stewartia ovata or mountain camellia.  As you may know, I looooove Stewartia pseudocamellia .  In fact, one of the only downfalls of that plant (to me) is that it is not native.

This species however is native to the southeast US mountains.  And while it's not as elegant as S. pseudocamellia -- the bark is not as lustrous -- I am desperate to plant this on an upcoming project.

You can see the flowers on the ground above and below -- it appears we were just a week away from seeing this at its peak.

The flowers are very similar to S. pseudocamellia, and both species are in the Theaceae family, which does indeed include Camellia itself.

Sadly, the plant seems to be somewhat rare -- a brief google search came up with a few native specialists that provide 1 gallon specimens, so I'll need to keep my eyes peeled for large specimens.

Cunninghamia lanceolata

I think anyone who has been teaching plants (horticulture or botany) for any length of time gets comfortable with telling students 'I don't know.'  It's bedeviling how many different species are out there and after a few years, you aren't too concerned with appearing as if you don't know *everything*.

 

That said, it is a thrill when you encounter some horticultural oddity in the landscape and you know right away what it is.  In this case, I instantly recognized it because on some cold winter in New York, I saw it at the Japanese Garden in the Brooklyn Botanic Garden (in fact, I met this plant the same day I encountered Wollemia, parachute plant and Asclepias physocarpa

Above you can see the iridescent suckers at the base of the trunk. Evidently these suckers can be harvested with ease.  The foliage is a bright light blue (this is probably a 'Glauca' cultivar) and is distinctive in that the leaves fall from the stem in two ranks, much like some species of Taxus.  In fact, this plant was classified in the Taxodiaceae family for some time, though is now considered a Cupressaceae plant.

 The spiney leaves are very sharp -- frankly I'm surprised this isn't in the Pinaceae family, related to Picea -- and when the leaves fall to the ground and dry they can become a fire hazard.

As the name implies, the plant is native to China and islands off the coast of China. There, the wood is frequently harvested for timber.

When you reach the edge of Kenilworth Aquatic Gardens, there is a long boardwalk that leads you to the Anacostia River.  It's a lovely view with very little to indicate you are within a major city.  The semi-wet soil in which the pink perennial below is growing is a typical habitat for Vernonia noveboracensis or New York Ironweed.

New York ironweed is a native to the northeast and though it's regularly found on the edges of streams, it can also fare well in drought or heavy soils.   It can easily reach heights of 6-8' and works great with other late summer flowers like sunflowers and goldenrod.

Finally, the deep magenta blossoms (like all flowers in the Asteraceae family, the flowers are composites with disc and ray florets), add a powerful pop to an otherwise dull late summer garden.

Kenilworth Aquatic Gardens

Last Saturday, my students and I had class at the Kenilworth Aquatic Gardens.  If you haven't been (and you live in the DC area), definitely check it out.  We lamented the fact that we were just a few weeks too late to enjoy what had to have been an amazing show of lotus (Nelumbo nucifera).

Here are a few photos.  I'll elaborate on a few new species later in the week. 

Enjoy!

Quercus falcata

My students and I passed this tree at the National Arboretum a few weeks ago and it was downright impossible not to stop and take a longer look.  The graceful lean to it, in addition to the backlit sun, made the tree look downright enchanted.

 

It was obviously an oak, but I was unsure which species.  Turns out it is Quercus falcata or Southern red oak or Spanish oak.  Its northernmost range is New Jersey, but the tree is so incredibly sensitive to compaction, you rarely encounter it. 

More on the National Arboretum's 'Ruins'

A little over a week ago, I posted about the structure at the National Arboretum, which was built from unused columns from the Capitol.