Wednesday, September 19, 2012

Why is fall best for planting?

Jason Holmes, center, 
advises customers about plant selection
at last year's Fall Plant Sale

By Jason Holmes

Ahh, the season of fall is almost upon us, and we gardeners are coming out of summer semi-hibernation, during which we emerged only to water the plants we planted in early spring, hoping they made it through those hot, dry summer months.

Many of us know that fall is the best time to plant shrubs and trees. We hear it all the time. But let’s face it, we see plants we love, with those nice big flowers or that beautiful combination we just have to have, and that sage advice sometimes gets forgotten. For me, buying plants in spring is often an impulse, and I spend much of my time watering those plants on 90- to 100-degree afternoons.

People often ask, “Why is fall the best time to plant?” The answer is simple: As the plants go dormant above ground, roots will continue to grow underground until the ground temperatures fall below 40 degrees Fahrenheit.  So for most of the country, this statement is true from mid-September through mid-December.

Here is an example: if you plant a tree in the spring, it must acclimate to the new site, producing new growth like leaves, flowers and sometimes fruits. It must also produce roots as well! This means you will need to water more often while your tree acclimates to its new situation before the summer heat and often dry weather arrives. Now, plant the same tree during the fall, and soon after the plant will begin to go dormant above ground, but the roots will still have several months to continue growing underground. This is giving the plant a “head start” for the next spring as it produces strong new growth.

Annuals and perennials are great to plant during the spring and fall. As long as they are watered until they are established, they fare very well. I love to plant perennials in the spring, as they are waking up from winter dormancy, because they grow to fill in a space quickly. Perennials are often faster to grow into a space as opposed to trees and shrubs, and this gives us a chance to plant these in both seasons. So it is simple: anyone can plant anytime they want. I just hope I’ve explained well enough why fall is so ideal.

To help prepare you for your fall planting blitz, Sarah P. Duke Gardens will have its Fall Plant Sale on Saturday, Sept. 29, from 9 a.m. to noon. We will have a great variety of bulbs that bloom in late winter to early summer, fantastic perennials, useful herbs for cooking, and many unusual shrubs and trees, too. Many of these plants are propagated from Duke Gardens by dedicated staff and volunteers, who will be there to answer any questions you may have about gardening or plants in general.

If you want first dibs on all the plants, consider joining Friends of Duke Gardens, so you can attend the member pre-sale at 8 a.m. Non-members can join on site. Or call 919-668-1711 to join in advance. We hope to see you there.

Sarah P. Duke Gardens creates and nurtures an environment in the heart of Duke University for learning, inspiration and enjoyment through excellence in horticulture. The Gardens is at 420 Anderson St.

Columnist Jason Holmes is curator of the Doris Duke Center Gardens at Sarah P. Duke Gardens. This column first appeared in the Durham Herald-Sun.