Take a look at the USDA Plant Hardiness Zone map and you can see just how wide the variations in temperature can be across this great land of ours. The zone in which you live can play a major part in determining whether a particular plant will survive and thrive or wither and die.
I was reminded of this while looking at a Web site hosted by the United States National Arboretum (USNA) in which they list some selected woody plants and the average annual minimum temperature range in which they can be planted. Here are a few examples:
Zone 1. Below -50 F. Quaking Aspen, Dwarf birch, Lapland rhododendron
Zone 2. -50 to -40 F. Paper birch, Eastern larch
Zone 3. -40 to -30 F. Common juniper, American arborvitae, Japanese bayberry
Zone 4. -30 to -20 F. Sugar maple, Chinese juniper, Virginia Creeper
Zone 5. -20 to -10 F. Flowering dogwood, Japanese yew, Boston Ivy
Zone 6. -10 to 0 F. Japanese maple, English ivy, Castle Wall Holly
Zone 7. 0 to 10 F. Hatfield yew, Bigleaf maple, English yew
Zone 8. 10 to 20 F. Cherry laurel, New Zealand daisy bush
Zone 9. 20 to 30 F. Fuchsia, Tasmanian blue gum, Asparagus fern
Zone 10. 30 to 40 F. Bougainvillea, Royal palm
The plants are listed under the coldest zones in which they normally succeed. Of course, in most zones there are many more, and you can find more examples along with a very detailed zone map at the USNA site http://www.usna.usda.gov/Hardzone/hrdzon4.html#2 You can click on a direct link to that page when you find this column archived at my Web site www.landsteward.org
There are a few plants that seem to do well in almost every zone with the exception of areas that get a really severe deep freeze in the winter. One of the most popular of the hardy groups is Buddleia, often aptly named the Butterfly Bush.
They are hardy in Zones 5 through 9, but even if you live in a colder zone you can still plant Buddleia. Over the winter, they’ll simply die back, but they’ll return as strong as ever the following spring.
Here are some of my favorite Buddleia varieties.
Buddleia Royal Red. This is a 1928 hybrid growing to about 6 or 7 feet tall with long fragrant panicles of deep violet flowers. Yes, it’s a bit of a stretch to call them red, but butterflies are colorblind anyway!
Buddleia White Profusion. This one is a little taller, reaching to 9 or 10 feet in height. It produces tiny, individual flowers grouped in long, dense trusses that have a very delicate scent.
Buddleia Nanho Blue. Treated to an area with full sun, the Nanho can reach up to 8 feet or more with dense masses of closely packed blue flowers.
Buddleias red, white and blue. Very patriotic. But you can also find the Buddleia Honeycomb, a Dutch variety with ever-blooming orange-eyed yellow flowers, and the Buddleia Black Knight with distinctive grape-violet blooms that look spectacular in front of a backdrop of gold foliaged plants.
At the other end of the scale are plants that can only be planted in the warmer zones if they are to survive a winter.
Varieties of the ever-popular Crape Myrtle are good examples of plants that should only be planted in USDA Zones 6 through 9. One of my favorites is Crape Myrtle Dwarf Victor with bright red blooms that can last almost three months. Plant a few Victors in a group or create a hedge that will top out at around 4 or 5 feet and the effect of the color is truly stunning.
Even smaller is the Crape Myrtle Dwarf Chickasaw, reaching only 2 or 3 feet tall with densely-branched deep green foliage and pinkish lavender conical flowers.
Smallest of all is the Dwarf Pokomoke, a Crape Myrtle that is 1 to 2 feet tall and is an ideal container plant for a sunny patio.
The Plant Man is here to help. Send your questions about trees, shrubs and landscaping to steve@landsteward.org and for resources and additional information, or to subscribe to Steve's free e-mailed newsletter, visit www.landsteward.org
