Wild Weather and Winter Greens

This first month of winter has been true to Kansas City: a manic-depressive wild ride! We have had two days with highs in the 60s, inch rains twice, plus sleet and 2 inches of snow. The predicted "coldest Arctic blast in a decade" did not materialize. Yes, it was cold but not even close to record cold. At our official weather station in a cold pocket the temperature bottomed out at zero, twice (the month of the terrible twos?). There are still two more months of winter to go and March can go either way. The cold weather did no damage to any plants that I can see -- it was nothing out of our "ordinary."

Below are some images of the many wonderfully ornamental plants that really show off at Powell Gardens in the winter. I feel like a broken record pushing the beauty of winter and its ornamental plants -- it is something I always consider while acquiring plants through the year. My how these plants can really shine now, especially when viewed from indoors. I do recommend a new book on winter gardening: The Garden in Winter by Suzy Bales. Suzy (from Long Island, New York) has spoken at Powell Gardens and I had the pleasure to show off our grounds to her pre-Easter freeze in 2007.

American Holly (Ilex opaca) is perhaps the classic winter garden plant and such a symbol of holiday decor. As with all hollies, only female plants produce fruit and most need pollinators nearby (some hybrids produce fruit without pollination). Plant this long-lived, slow but beautiful tree for future generations to enjoy! It is hard to find and generally available only by mailorder in Kansas City. There are magnificent small trees in the 30-40 foot range in the older parts of Kansas City and its older suburbs. This evergreen is native to southeast Missouri and part of Missouri's Grow Native! program.

Greenleaf Holly (Ilex x attenuata 'Greenleaf') is a hybrid between the American Holly and Dahoon (Ilex cassine). Because this holly has hybrid vigor and grows very fast and is easy to propagate it is readily available at nurseries. It has smaller fruits that the birds really relish but is much less hardy then American Holly. It grows more int the 20 - 30 foot range in our area. Be sure to plant it in a sheltered place when outside Kansas City's "heat island." Yes, the core of the city is usually 5 degrees warmer than the surroundings - year round! This plant has completely died back here (2001) but recovered well.


Blue Princess Holly (Ilex x meservae 'Blue Princess') is a beautiful hybrid shrub holly that is very hardy. It is a cross between a cold hardy holly (Ilex rugosa) from Hokkaido(north island), Japan and the beautiful yet non-hardy English Holly (Ilex aquifolium). There are several cultivars in this group but Blue Princess has the best, glossy leaves with a hint of blue. We also have 'Blue Maid' in this group with 'Blue Stallion' as pollinator. This holly does not like extreme heat and the big swings of temperatures we can have here. Our plants killed to the ground one year (2001)but have completely recovered. I found it odd they died back when Southern Magnolias growing above them were uninjured! They are against the north wall of the Visitor Center where they stay cooler and shaded during the hot summer. This hybrid holly is readily available in nurseries and even big box retailers.


China Girl Holly is another hybrid holly using the hardy holly (Ilex rugosa) but it is crossed with the Chinese Holly (Ilex cornuta). This hybrid is much more apple green in leaf and stem as well as inheriting heat-tolerance from the China Holly. We grow these shrubs on the south side of the Visitor Center where it gets very hot in summer. The pollinator is aptly named 'China Boy.'


Acrocona Norway Spruce (Picea abies 'Acrocona') is a personal favorite of "dwarf" conifers. The abundant cones are very ornamental in winter (they are bright magenta in spring when emerging as female flowers!). This pine grows slowly to be at least 8 feet tall and wider than tall.


The flat sprays of golden foliage of this Rosenkranz Arborvitae (Thuja occidentalis 'Rosenkranz') create some warm color in this season. The green backdrop (a weeping common juniper) helps set the color off. This beautiful dwarf conifer is not readily available in local nurseries.


The blue needles of the St. Mary's Broom Blue Spruce (Picea pungens 'St. Mary's Broom') are so luxurious in winter. This true dwarf conifer is a favorite of Marvin Snyder of Overland Park, past President of the American Conifer Society and inspiration for our dwarf conifer garden at the north end of the Visitor Center. I like its contrast with the orangish Angelina (fore and background) and reddish Wehenstephaner Gold sedums which are neighboring low groundcovers.


Vintage Gold False Cypress (Chamaecyparis pisifera 'Vintage Gold') is a beacon of gold in the Fountain Garden. It is probably our most yellow of winter evergreens and has a very beautiful texture to the needles and sprays of young foliage.


Little Bluestem (Schizachyrium scoparium) though not evergreen is also at its showiest now when the dried, weathered stems and silky seed heads sparkle when back lit on these low sun angle days. This native prairie grass is a tough perennial that requires full sun and average soil. No extra water is ever required once it is established!

Grass Green in Winter?

Few evergreens remain grass-green in winter but one is just that: a grass!

This is a (now) massive stand of Yellow-groove Bamboo (Phyllostachys aureosulcata) growing as a screen behind the Rock & Waterfall Garden. This woody grass can grow up to 25 feet tall (these are a mere 15 feet). It is a running bamboo so be prepared to control it or cut the new culms (sprouts) in spring. We are harvesting canes off this massing for uses in garden staking and trellising.

A closeup of its culm (stem) reveals a flat side that is yellow -- this is how the Yellow-groove Bamboo gets its name. The invasive shoots of this plant in spring are edible but the main species utilized in Asian cooking as bamboo shoots is Sweet Shoot Bamboo Phyllostachys dulcis. Edible shoot bamboos will be on display in the new Heartland Harvest Garden.


The feathery mass of green is the native bamboo Switchcane (Arundinaria gigantea). This grass is native in southern and southeastern Missouri and quite hardy here. This massing is a backdrop in the Rock & Waterfall Garden. Switchcane is the only evergreen shrub of any size (8 feet) native to Missouri. It provides good cover for wildlife and makes a good screen in natural landscapes.


Steeple-shaped evergreens of Green Giant Arborvitae (a hybrid between Giant Arborvitae a.k.a. to lumbermen Western Redcedar Thuja plicata and Japanese Arborvitae Thuja standishii) really put on a show along the trolley drive to the Chapel. This was originally a mass planting of Scotch Pine. Knowing that disease was ravaging that pine, we planted little one gallon trees of Green Giant Arborvitae from the Botany Shop in Joplin, MO, in between the Scotch pines. The Arborvitae are now 18 feet tall while most of the Scotch Pines are dead (except the one on the right). Green Giant Arborvitae also are shunned by deer!


The blue-green needles of Vanderwolf Limber Pine (Pinus flexilis) are quite showy in this season. We actually have had trouble with Limber Pines getting a needle blight but this one has so far been immune. As with most plants from high mountains, they should be planted in full sun with good air circulation in our hot, humid climate zone.


One of our bluest needled evergreens is the 'Hoopsii' Blue Spruce (Picea pungens) the state tree of Utah and Colorado. Its icy blue needles are so beautiful and striking in the winter landscape.


Loblolly Pine (Pinus taeda) has been a good performer for our heavy clay soils but is pushing its northern limits here. I actually like its apple/yellow-green, long needles. Trees at Powell Gardens (along the nature trail and other wild areas) were planted by the Boy Scouts long ago and the tree depicted is actually a self-sown seedling transplanted to this location south of the Rock & Waterfall Trolley Stop.


Evergreen certainly does not mean "green." The evergreen Leatherleaf Viburnum (Viburnum x rhitidophylloides) leaves turn shades of purple in winter -- this year more red than purple!


Here is a closeup of the winter foliage of the Leatherleaf Viburnum this year. It has beautiful texture as well as color for the winter landscape.



Powell Gardens is a perfect place to see a variety of evergreens in the winter landscape; and you will notice many of them certainly are not green in the winter but a wonderful array of green blended colors including reddish, orangish, yellow, bluish and purplish! All photos taken by Alan Branhagen on December 12, 2008.

Tardily Deciduous

Yes, there is a horticultural term for deciduous plants that hold their leaves into winter: tardily deciduous. As the temperatures get colder these plants will gradually lose more and more leaves until they are nearly bare by mid-winter.

No, these Northern Sweetbay (Magnolia virginiana var. virginiana) magnolias in front of the Visitor Center are not sick! They are just now beginning to lose their leaves as the cold weather has arrived. Sweetbay magnolias are generally not recommended for such a windswept site but because the planting beds are so poorly drained (wet!), this was a good choice here: Sweetbays are hardier if they have constant moisture and are native to wetlands. As these small trees mature (15-20 feet) they will create a more comfortable space to sit in front of the Visitor Center. The sweet scent of their late spring and summer blooms is intensely lemon-like.

Here is an evergreen cultivar of the closely related Southern Sweetbay (Magnolia virginiana var. australis) 'Milton'. You can see its leaves are still dark green above and blue-green below. Severe cold (-10F) can damage the leaves and make them drop. Southern Sweetbays are usually more tree-like (20-30 feet here) and less bushy than their northern cousins.


Can you spot the tardily deciduous plant in this image? It's the front and center ball of olive green: Winter Honeysuckle (Lonicera fragrantissima). As the weather gets colder more of its leaves will discolor and drop. The pinkish brown leaves to the left are the marcescent (dead leaves that don't drop) foliage of the White Oak (Quercus alba) while the dark green plant in the background is the truly evergreen Southern Magnolia (Magnolia grandiflora 'Twenty-four Below').


A close look at a twig of the Winter Honeysuckle shows a swelling bud: it is a flower bud that may open as soon as next month if we have a spell of mild weather. Winter Honeysuckle has very strongly lemon scented flowers that perfume a wide area. The flowers can be damaged by severe cold but the shrub always continues to sprout new flowers until mid-spring. This non-native honeysuckle is not an invasive like many of its cousins. It becomes a huge shrub that can be trimmed up like a little multi-stemmed tree.


Looking out the windows from the Visitor Center the evergreen Southern Magnolias defy the winter season with lustrous green leaves. Few broadleaf plants are evergreen in our climate. These are some of the hardiest selections and we wonder how they will fare if we again have our record low temperatures.


Looking north from the Visitor Center you can see how the landscape around the Visitor Center has many plants with winter interest -- evergreens! The pair of potted plants are Bracken's Brown Beauty Southern Magnolias, the center left plant is an American Holly (Ilex opaca) and the center right plant is a Lacebark Pine (Pinus bungeana). Stay tuned for more on evergreen plants in the next blog...