UNITED STATES—Stormy winter weather always reminds some of us that our trees need some attention. Wind can break limbs. If the weather gets really nasty, trees can be destabilized by strong wind, particularly if the soil is moistened by rain. However, the truth is that arboriculture, which is the horticulture of trees, is important throughout the year. We just become more aware of it when weather threatens.

Not only is arboriculture important throughout the year, but it is also the most important aspect of horticulture in most gardens that are outfitted with trees. After all, trees are the most significant features of such landscapes. Their shade affects the homes and garden spaces around them. If they drop limbs or fall, they can cause significant damage. Many get far too big for us to maintain.

This is why we need arborists, the horticulturists who specialize in trees. Arborists can evaluate the health, stability and structural integrity of trees, and prescribe any necessary arboricultural procedures. In order to issue a permit to remove a tree, most municipalities require an inspection and report from an arborist who is certified by the International Society of Arboriculture, or ISA.

ISA Certified Arborists have passed an examination of their arboricultural expertise, and maintain their certification by continued involvement with ISA educational seminars, workshops and classes. The ISA is the standardizing resource for the promotion of the most important arboricultural technology, and maintains discriminating standards. ISA certification is quite a commitment, www.isa-arbor.com, the website of the ISA, is an excellent resource for anyone in need of the services of a certified arborist. The registry of arborists can identify and find an arborist directly by name, or regionally by city or ZIP code. The site is also useful for information about proper arboriculture and trees, for those of us who maintain our own small trees, or want to select new trees.

Trusting the wrong professional to maintain trees can be very risky. Even gardeners who are proficient at mowing lawns and shearing hedges may not be adequately knowledgeable about proper arboriculture.

Instead of correcting problems, improper pruning can disfigure trees and limbs, and actually compromise their structural integrity. Sadly, it is not uncommon for otherwise healthy, stable and well structured trees to be ruined by those hired to care for them.

Highlight: sweet pea shrub

It may not always bloom profusely, but sweet pea shrub, Polygala fruticosa, blooms sporadically through most of the year. Even when not much color is evident from a distance, a few flowers can likely be found on closer inspection. For some reason, bloom seems to be quite colorful now. Bloom phases should be more profuse in spring and summer. The pea flowers are soft purplish pink.

Mature plants might only get to two or three feet tall and wide, but have the potential to get larger. They are usually a bit wider than tall, with a nice rounded compact form. The evergreen foliage is slightly grayish light green. Sweet pea shrub prefers full sun exposure, but can get roasted in hot spots. A bit of shade should not be a problem. Once established, it does not need too much water.