Wednesday, December 16, 2009

Winter Landscape Tips

It is the season to enjoy the beauty of evergreens and other plants with winter interest. Powell Gardens with its 7,000 varieties of permanent plants on display, offers a good place to see a inordinate variety of plants in the landscape.
The evergreen spires are Green Giant Arborvitae (Thuja 'Green Giant') and look rich green and boldly textured.

Backlit in our winter sun, the same grove of Green Giant Arborvitae looks dark and ominous! Evergreen trees including the Green Giant Arborvitaes are best sited in the landscape where they will break the prevailing winter winds. That means planting them north and west of your home, the perfect setting to view them from in winter. They also diminish the wind on your home which can cut heating bills by between 10 and 25%!!! Planting evergreens on the south side of your house means you will see what is depicted here and they will block the wonderful, warming winter sun. The shadows of evergreens can create winter patches of snow and ice that can be a nuisance on walks and driveways.

A very few evergreens look at their best when backlit in the winter. The Inkberry Holly (Ilex glabra) is one such plant that simply sparkles when backlit in the winter sun. Inkberry Holly is a medium to large shrub and makes a wonderful natural winter screen but doesn't get tall enough to block the sun to most home's windows. This shrub is often used as an American native substitute for boxwood but it never stays that dense and opens up into a more free form as it ages. Use boxwood for formal hedging and tidy evergreens, not Inkberry.
Now that we have had two arctic outbreaks, it's nice to stay indoors and look outside at the landscape that surrounds you and think about plant/landscape additions for next spring. Looking out the Horticulture Building's southwest window we see a Kentucky Coffeetree (Gymnocladus dioicus) which is the perfect plant for this location. A shade tree at the southwest corner of your home will help shade your home during the hottest sun of summer. Air temperatures under a shade tree are as much as 18F cooler. Shade trees are 24/7 living air conditioners that also absorb carbon dioxide, dust and other particulates (asthma rates for children fall by a quarter in areas of high tree population) and release oxygen as a biproduct of photosynthesis.
The shadow of the Kentucky Coffeetree on the Horticulture Building also demonstrates why Coffeetree is such a ideal building shade tree. The plant is very open in the winter and allows maximum sunlight to penetrate now -- warming the building! Choose sturdy shade trees with open crowns and coarse root systems that won't invade utilities. Other good examples include Bur, Chinkapin, Post, Northern Red and Shumard Oaks, Baldcypress and Cucumber Magnolia. Bad choices would be Silver Maple, Cottonwood and Sweetgum.
A view out my screened office window shows the Possumhaws (Ilex decidua) cloaked in vibrant red berries. Everyone who comes to visit is immediately drawn to these vibrant trees in the winter landscape. Not only do they provide an invigorating warm color in the landscape now but they attract wildlife that provides drama in the landscape. This is the winter larder of a possesive mockingbird while robins, bluebirds and waxwings will come in to feed on occasion too.
Other deciduous hollies like this grove of Sparkleberry Hollies (Ilex 'Sparkleberry') in the Perennial Garden equal possumhaw for vibrant color in the winter landscape. We did not experience below zero temperatures here so the colors have remained vibrant. Choose Red Sprite Winterberry as the smallest deciduous holly maturing at 5 feet to Winter Red and Sparkleberry which reach about 8 feet in height. Possumhaws eventually become small trees so plan on them reaching 20 feet in height or more over a long period of time. Remember only the female plants have these beautiful berries and an appropriate male cultivar is needed nearby for pollination. Sparkleberry holly requires 'Apollo' or 'Southern Gentleman' holly as a pollinator.
A view across the parking lot to the Maintenance area reveals well placed evergreen shrubs and ornamental grasses. These effectively screen the view at almost all seasons though the grass is cut back in spring but quickly fills in by early summer. The shrubs are Leatherleaf Viburnums (Viburnum x rhitidophylloides) and the grasses are maiden grass (Miscanthus sinensis). Take a look out all your windows now and if there are any unsightly views, plant a screen for them next spring!
A walk through the Powell Gardens perennial garden reveals a great balance of all types of plants from groundcovers to deciduous and evergreen shrubs and trees. A diversity of plant forms and their proper placement really does create a most inviting landscape. Don't experience cabin fever and plan a winter visit to Powell Gardens to observe all the subtle beauty of winter and get ideas that will enrich your home landscape.

1 comment:

the wild raspberry said...

Hey Alan...
I like the blog~
I couldn't find your email address anywhere so I'm leaving you this note here.

I just did a blog post about our trip out to Powell today and thought I would share it with you.

{yes I am a blogging addict}

Have a wonderful weekend and a very Merry Christmas!