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Digging In: Scott Aker

Periwinkle Needs a Haircut

By Scott Aker
Special to The Washington Post
Thursday, April 7, 2005; Page H07

Q Underneath a large holly tree, I have about 120 square feet of periwinkle, Vinca minor, that has been neglected for a long time. I have seen little growth in the past two years. How can I encourage more robust growth?

A Try mowing it now. The vines of vinca root at intervals, and a new crown develops wherever it pegs itself into the ground with these roots. By shearing off the old mass with a mower, you will encourage new vigorous growth from these crowns. Be sure to set your mower at its highest setting and check for rocks and other objects before you start to mow.

Although vinca is very tolerant of shade, it will not form a continuous carpet of green in really deep shade, such as under an evergreen conifer, magnolia, maple, beech or holly. You could remove some of the lower limbs of the holly to allow more sunlight to reach the vinca.

However, I find bare-stemmed hollies look unnatural. I prefer to let the lower branches of the holly grow close to the ground as they do in the forest, and let the vinca be a little thin.

What are the rules for naming a flower after someone?

This privilege usually goes to the scientist who discovers a new plant in the wilderness or the breeder who raises a new hybrid or variety. In short, it is a rare and hard-won honor.

New plants still are being discovered, particularly in the tropics. The person discovering the new plant must know that it is different from related plants and then prove it scientifically, in part by describing every aspect of its anatomy and collecting pressed samples.

The description is published in botanical periodicals, and botanists have a chance to tell you that a species name already exists for your new plant (in other words, it's already been discovered) or that it is not different enough from a previously described plant to be its own distinct species. Even the most intrepid expert is unlikely to find a new species in a heavily populated region.

It is easier to name a new purposefully bred and selected variety of plant, known as a cultivated variety or cultivar.

It is denoted by single quotes, hence: Magnolia grandiflora 'Edith Bogue' designates a southern magnolia that was selected for its various qualities. Someone sent a nice magnolia from Florida in 1920 to the Montclair, N.J. garden of Edith A. Bogue, and someone decided to name the tree after her. To name a cultivar of a plant after someone, you'll have to select a plant with some outstanding attribute that is not equaled by existing cultivars of the same species, or you'll have to start a breeding program of your own. The magnolia variety 'Edith Bogue' is more pyramid-like and smaller than the species and has superior winter hardiness.

To claim a cultivar name, you have to record it with the official registrar for the category of plant involved, who may not accept it as new or worthy. More information on registering a cultivar is available from the International Society for Horticultural Science at www.ishs.org/sci/icraname.htm.

Some registrars frown upon the use of someone's name to denote a cultivar because it doesn't say anything about the special attribute that the plant was selected for. Similarly, many botanists prefer to give new plants a species name that bespeaks its native region or indigenous name.

You may find it much easier to get a star named for the person you are thinking about.

Scott Aker is a horticulturist at the U.S. National Arboretum.

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