JARS v46n3 - In Search of Better Natives

In Search of Better Natives
Gary Koller
Jamaica Plain, Massachusetts

Northern landscapes have been greatly enhanced by the planting and successful cultivation of Rhododendron catawbiense and Rhododendron maximum . Both species have been cultivated at the Arnold Arboretum for well over a century. They were first collected and cultivated under the guidance of Charles Sprague Sargent and have undergone a long period of trial and observation. After conducting a review of its holdings in the genus Rhododendron , the Arboretum has embarked on a program to strengthen its species representation, especially those native to North America. The objective will be to seek out superior flowering clones or plants which combine compact habits with superior flowering. The goal is to seek only wild occurring plants from which specific collecting information can be gathered and maintained. We are not interested in garden forms and hybrids but are interested in nursery selections, originally gathered from the wild, for which specific collecting site information is available.

This note is to request assistance and offer a challenge. First the assistance! Gardeners, horticulturists, botanists and naturalists have combed and are combing mountains and valleys where these plants grow naturally. They must know of or must be finding individuals or colonies of plants which are significantly different from their neighboring kin. This discovery is evident in selections such as Rhododendron catawbiense 'Glass', R. c. var. album 'LaBar's White' and R. maximum 'Mt. Mitchell' and R. m. 'Aphrodite' all originally found in the wild. We are attempting to identify and make contact with individuals with that keen eye who can help us locate plants. We will work with people to evaluate the selected plants over time with the goal of establishing better types for long term deployment in the collections of the Arnold Arboretum. As an example, Rhododendron maximum as represented in the nursery trade is a strong and dependable grower, with a late flowering season, but the blossoms are generally smaller, less abundant and of a poor color. There must be forms which will thrive in more sunny locations which have larger flowers, fuller flowers, better whites, stronger pinks, a more tight and tidy habit or better foliage which might include colors or markings in the foliage. This is what we are seeking for both Rhododendron maximum and Rhododendron catawbiense . The best, as evaluated by our local rhododendron specialists, would be stock increased for eventual introduction to the nursery industry. The Arnold Arboretum is interested in protecting the rights of the person who discovered or located the original wild plants and would work cooperatively to name, register, stock increase and distribute those plants selected for wider distribution.

The challenge to members of the American Rhododendron Society is this. Tear yourselves away from your garden and explore the countryside where these plants occur naturally. Over the centuries Japanese gardens have been enriched by Japanese plants-people with sharp eyes who knew how to seek the unusual and the exceptional from their native plants. In North America we tend to think of our native rhododendrons as little more than common wild plants and often fail to take a thoughtful or careful look seeking out the widest possible variation useful to garden making. The challenge for all of us is, to open our eyes and to look more critically seeking superior individuals or populations from which to gather propagation materials for trial in our gardens. We do not advocate taking the original plant from the wild but instead wish only to have the opportunity to take cuttings or scions for grafting. Exciting selections have already been made but what additional selections await discovery? Let's take a look at these plants and together discover their potential for the gardens of today and tomorrow.

If you are interested in this process of discovery and already know of superior plants, or someone else who does, we welcome you to let us know by writing to Gary Koller, Senior Horticulturist at the Arnold Arboretum, Jamaica Plain, MA. Perhaps cooperatively we can achieve progress more quickly than if we attempt to go it alone.