Neat points for good health
One gardener discovers that a favorite low-mess tree in his yard is a type that has a reputation as a slob. Another plants a tree touted for neatness and finds it to be an unqualified mess. What gives?
In both cases, the “right plant, right place” axiom is probably involved. Put a plant into a site where it can grow with gusto and it may be healthy enough to rise above its bad rep. Condemn even the neatest species or variety to a site where it does not receive the amount of light it needs, gets too much or too little water, has insufficient root space, or is saddled with other handicaps, and you may indeed find yourself with a mess on your hands.
Is seedlessness worth it? The nose may know!
Some trees that do not produce fruit or seeds are naturally sterile clones. The barrier to fruit formation may be genetic. Alternately, it may be the result of flowerlessness (golden thornless honeylocust is an example) or the inability of pollinators to work the flowers (double-flowered ornamental cherries such as ‘Kwanzan’). It’s a good idea to check the facts before you decide a sterile clone is right for you. You wouldn’t want to count on a plant for its flower color only to realize years after planting that it’s sterile by virtue of flowerlessness.
Other seedless plants are varieties from “dioecious” species—those that have separate male and female plants. In the species Ginkgo biloba, for instance, some individuals bear only flowers with fruit-producing parts. We call these females. Other individuals produce only pollen-bearing flowers. Ginkgo ‘Windover Gold’ is one of these “male” ginkgos. Ash (Fraxinus), cottonwood (Populus), box elder (Acer negundo), cork tree (Phellodendron), and mulberry (Morus) are other dioecious species found in the landscape.
If a tree you plant is sterile because it is a male plant, it is certain to up the pollen count in your area. All of the trees listed above are also wind-pollinated, meaning the pollen they produce is lightweight and airborne, rather than heavy and sticky for transport by insects. Wind-borne pollen is a potential allergen. The planting of large numbers of male trees has been cited as a factor in the increased pollen count in some cities.
Evergreen species do shed leaves and needles. We consider pine, spruce, yew, juniper, rhododendron, boxwood, and others to be evergreen because they rarely shed all their foliage at once.
Some evergreens shed their oldest foliage once a year—arborvitae and pine are notable examples. Those who suddenly take notice of the fall needle drop may even be alarmed. Others such as spruce, yew, and boxwood shed continually. If you are looking for an evergreen that will overhang a walkway you wish to be clear of debris, it may be better to select a species that sheds once a year, for limited clean up.