When you talk about your basic spring-flowering trees, the subject eventually turns to dogwoods. After all, they're the revered trees of the season, symbols of all that's pure and good about springtime. The brightness of their white floral bracts lacing the East Texas countryside every March brings a smile to your face.
Wait a moment! Did we just read East Texas? Yep, that's where dogwoods call home, and if we want them to be happy in our North Central Texas environment, we're going to have to put out extra effort (and organic matter).
Follow the four-word dogwood dogma: Dogwoods need acidic soils. Actually, they need water-soluble iron in greater quantities than most of our locally native trees and shrubs. Iron becomes insoluble in alkaline soils, which is why we see so much iron deficiency (chlorosis) with dogwoods, East Texas pines, azaleas, gardenias and wisterias here.
So, what can a gardener do to move past the roadblock? You can prepare a totally organic planting medium for the dogwoods. It's basically the same bed preparation that you'd do for azaleas, gardenias and camellias, except that you have to do more of it to accommodate the larger root system of dogwoods. (For the record, this type of soil preparation is not practical for the much larger East Texas pines. They should not be attempted in areas with black, clay gumbo soils.)
Your goal in making a planting bed for a dogwood is to have a mix of equal amounts of Canadian peat moss and finely ground pine-bark mulch in a bed 18-20 inches deep and 6-8 feet across. You can remove topsoil 6-8 inches before bringing in the dogwood mix if you'd like the bed to extend partly into the ground. Plants that combine well with dogwoods include hostas, ferns, ajuga and Vinca minor trailing ground cover.
Dogwoods are native to forested lands. While you'll see them growing in full sun in East Texas occasionally, they're usually tucked back in the shadows of taller trees. In North Texas, they will do best with morning sun and afternoon shade. Do not allow them to wilt dramatically. These are not plants that endure drought very well. Their leaves will scorch badly.
Other than iron deficiency, dogwoods don't have a lot of problems locally. Fertilize them with an all-nitrogen, lawn-type fertilizer immediately after they bloom. That's also a good time to do any light trimming and shaping. Repeat the feeding in early summer and again in early fall. Add a sulfur/iron product should chlorosis appear.
You're likely to find several varieties of dogwoods available in nurseries now. They're very compelling, and the plant you like may not be there an hour later. Nurserymen tend to have their best supplies when demand is at its greatest in the spring.
Many of us prefer the bright white of the native species. If you do, and want to go one step better, consider the grafted variety Cloud 9. It has more and larger floral bracts. It makes a beautiful specimen once it begins to mature. You may have to hunt just a little to find it, but it is available.
If you prefer something a little more novel, consider Cherokee Chief or one of the other red-flowering selections, or Rubra or another pink type. You'll even find variegated types. Those are for impatient gardeners who can't wait for iron chlorosis to show up on its own.
Dogwoods really are trees for all seasons. Spring is their prime time in the spotlight, but their summertime foliage is dark green and attractive. It turns rich, crimson-red in late fall, and the flowers are followed by clusters of BB-sized fruit through the winter.
Finally, you may have noticed that we didn't ever refer to actual dogwood flowers. Like poinsettias and hydrangeas, dogwoods' flowering appendages are actually modified leaves that make up what botanists call floral bracts. They don't actually pop open like normal flower buds, nor do their petals fall when the bloom time has passed.
Neil Sperry publishes Gardens magazine and hosts the Texas Gardening radio show from 8 to 11 a.m. Saturdays and Sundays on KRLD/1080 AM. Reach him during those hours at 214-787-1080.