Sunday, December 25, 2011

Latin in Winter: Mahonia and More

Winter is an excellent time to examine the shape and hardiness of plants you want to add to your garden.  But, of course, it is important to know their proper names.  So, why not have another lesson in plant nomenclature?

First, I want to mention that the Latin we use in botany is not ancient spoken Latin.  It is a scientific system developed and adapted since the mid-18th century for study and classification of the natural world.  Each plant is identified first by its genus, say Acer, and then its species: palmatum.  Usually these names are “Latinized” from various languages.  Cultivar names are listed after the scientific name, such as ‘Atropurpureum’.  Acer palmatum ‘Atropurpureum’ is a Japanese Maple with wine red leaves.

Now, let’s start with Mahonia.
As in…
ma                   (not your Pa but your Ma)
HOE                 (the garden implement)
nee-ah             (the end of Romania or Albania).

The emphasis is on HOE.
You’re actually supposed to say mah-HOH-nee-ah, but that seems a little breathy.

Often known as Oregon Grape, Holly Grape or Leatherleaf, Mahonia is an upright, evergreen shrub with glossy, spiny leaves, almost like those of a Holly or Acanthus.  It is related to the equally prickly Barberries.  Mahonias always look rather sturdy and ferocious, as if they could withstand a ten-foot blizzard.  But they are native to temperate regions of Asia and North and Central America and prefer a little shelter in the garden.
Mahonia is popular for its racemes of fragrant, bright yellow, bell-shaped blossoms that bloom from late autumn to early spring, depending on the species.  The flowers develop into clusters of blue berries that birds adore.  Most plants at garden centers are cultivars of Mahonia aquifolium, M. fortunei, M. bealei or M. nervosa.  M. repens is often called Creeping Mahonia, because it grows less than a foot tall and spreads to over six feet wide.

M. eurybracteata ‘Soft Caress’ is a recent introduction that resembles a small bamboo with dark green leaves.  As the name suggests, it is the most touchable of all Mahonia.

In truth, Mahonia has never been one of my favorites.  Many gardeners inherit these evergreens in established landscapes but then struggle to incorporate them with other plants and tend to neglect their maintenance.  So the shrubs often appear sad and gangly and top-heavy.  But behold this lovely specimen I discovered last month in Richmond.
It definitely renewed my interest.

As in…
THOO-yah (like Booyah with a TH).
The emphasis is on THOO.
You could also think of it in baseball parlance:
“I threw ya out at home” without the r.

Thuja is an especially long-living conifer native to North America and Asia.  Its most common, common name is Arborvitae or tree of life – perhaps because of its long life span or because of its medicinal properties.  Thuja belongs to the Cypress family, but some people call it Red or White Cedar.  They often compare it to relatives like Cupressus x leylandii (Leyland Cypress) and Chamaecyparis pisifera (False Cypress).

Thuja occidentalis is Eastern Arborvitae, native to the northeastern United States and Canada, and Thuja plicata is the slightly more feathery western native, indigenous to the Pacific Northwest, Alaska and British Columbia.
Thuja occidentalis
Thuja evergreen foliage is soft and fan-shaped, like scaly coral silhouettes, and cultivars have been bred in almost every green imaginable from lemon lime with a hint of peach to the deepest inky hunter.  I personally love how the leaves become slightly bronze in the winter. Thuja is well-known for its easy care.  It is often grown in dense hedges without any need for shearing.  And unlike many evergreens, it can happily handle wet spots in the garden.
Threadleaf Thuja cultivar
T. occidentalis ‘Degroot’s Spire’ and ‘Smaragd’ are widely used as “exclamation points” in mixed borders.  But there are many other cultivars: T. occidentalis ‘Filiformis’ is a threadleaf, slightly weeping form; ‘Little Giant’ and ‘Teddy’ are dwarf cushions and ‘Nigra’ can quickly grow to over 25 feet tall.
Old Thuja occidentalis is like a giant green cloud in a neighborhood cemetery.

As in…
SOO-gah (the end of A Boy Named Sue and Lady Gaga).
The emphasis is on SOO.

Tsuga is also a conifer native to North America and Asia.  It is from the Pine family and has the needle-like foliage and cones we normally associate with evergreens.  Tsuga is commonly known as Hemlock but should not be confused with Conium maculatum, which is the poisonous perennial herb famously given to Socrates.
Here in the East, we usually find Tsuga canadensis, (Eastern or Canadian Hemlock), in our wooded mountains and hillsides and at our local garden centers.  T. caroliniana (Carolina Hemlock) is native to a much smaller region, mainly southwestern Appalachia.  In the wild, both species like cool, slightly humid, protected habitats and can grow into truly magnificent trees.
Several cultivars have been bred for home landscape use.  Some are broadly conical, like traditional, if-a-little-fat-on the bottom Christmas trees.  T. canadensis ‘Pendula’ and ‘Sargentii’ are weeping forms.  The charming ‘Jeddeloh’ is small soft mound with a natural indentation that resembles a bird's nest.  Dwarf forms, such as ‘Beehive’, ‘Jervis’ and ‘Stewart’s Gem’, are especially popular in rock gardens and hypertufa trough planters.  Iseli Nursery is a wholesale grower of dwarf conifers in Oregon, and their website provides a lot of information about employing these plants in garden beds and containers.
Weeping form of Tsuga.
A couple things to consider before planting Tsuga:
No matter what the size, all varieties prefer slightly shaded, protected spots.  They can suffer from wind burn, winter desiccation, drought and sun scorch.  They are also sensitive to salt spray.  Even if you don’t live at the beach, think about their proximity to roads and sidewalks and possible damage from snow-removal chemicals.

Many plant catalogs and retailers describe Tsuga’s range as Zones 4 to 8.  But I suspect it is more likely Zones 4-7 for T. canadensis and Zones 5-7 for T. caroliniana.

And finally, Tsuga is threatened in the wild by the Hemlock Woolly Adelgid (Adelges tsugae), an Asian transplant that was introduced to the U.S. in the 1950s.  The U.S. Forest Service reports Adelges tsugae was first found in Virginia in the 1950s, but other sources claim it traveled here via the West Coast, starting in the 1920s.  The Forest Service maintains maps of the spread of infestation since 1951.  I’m not sure how the Adelgid affects cultivated varieties.  But you should check with your local Cooperative Extension office to see if there are infestations in your area and if you can order Tsuga from certain companies.  For example, Maine, Michigan, New Hampshire, Ohio, Vermont and all of Canada are trying to limit the Adelgid’s range and will not allow shipments of Tsuga from the Mid-Atlantic and South.

As in…
lor-oh              (like Lori with an O instead of EE on the end)
PET                  (you pet your pet)
ah-lum             (you are an alum of your alma mater).

The emphasis is on PET.

Commonly known as Chinese Fringe Tree or Chinese Flower, Loropetalum has gained huge popularity in southern gardens over the last twenty years.  It is an Asian member of the Hamamelidaceae family and its strappy, starburst blossoms are similar to those of our native Witch Hazels and Fothergillas.  Loropetalum chinense has evergreen green foliage and white flowers.  I’ve read varying reports of its ultimate size in the wild – anywhere from five to twelve feet.

Loropetalum chinense var. rubrum is a naturally-occurring red-leaved, pink-flowered variety that has led to a wealth of Loropetalum options.  There are all sizes of mounding shrubs, and even some upright ones, that can be used as groundcovers, low hedges and ornamental trees in the garden.  Their leaves change hues throughout the growing season: black-green, muddy maroon, bronze-red, burgundy and plum.  And hot pink, bright fuchsia or rose flowers explode in April and continue blooming intermittently until November.
Loropetalums can grow quite large.
Still blooming in September.
L. chinense ‘Purple Pixie’ is from the Southern Living Plant Collection and has the most purple leaves I have ever seen.
All types of Loropetalum are evergreen in Zones 7 to 9; and are hardy down to about 15 degrees.  I believe they need some chill for flowers to set.  They all prefer slightly acidic soil and need regular water.  We are just on the edge of Loropetalum’s northern range, and I thought about pairing one with an established Crape Myrtle.  In the end, I decided I actually wanted deciduous foliage in that spot.  But I’m sure I’ll add a Loropetalum to our garden soon.

I hope you are having a wonderful Christmas and all your “long winter naps” are filled with dreams of beautiful gardens!

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