High Elevation Gardening Web Log "Blog"

When calling the Hotline, clearly state your name and phone number, provide a description of what ails your garden, and leave the best time to return your call. An MG volunteer will research the problem and return your call within 72 hours. The hotline phone number is (928) 774-1868, ext. 19.

The Master Gardener Program trains volunteers in horticultural knowledge and skills. After the training, the MG volunteers serve the community by answering gardening questions, conducting gardening programs, working on community beautification projects, and writing for the Master Gardener Column in the Arizona Daily Sun. The 2008 class is completing its requirements to become certified Master Gardeners by answering hotline calls. For information about the Coconino Master Gardener Program, leave a message on the hotline or email hbraun@ag.arizona.edu.

While not all questions are easily answered, volunteer Master Gardeners will do their best, using their training and the Arizona Master Gardener Manual and other resources.

Here are some Frequently Asked Questions:

Why are the pine trees along the interstate turning brown? Are they being attached by bark beetles?

The culprit is salt damage from the de-icing salts used on our roadways. De-icing salts harm plants by pulling moisture out of roots and reducing the uptake of water and nutrients to the plant. On conifers (pines, firs, junipers, and spruces), the damage appears as brown needle tips. Prolonged drought increases the damage. Browning usually appears in late winter and becomes more pronounced through spring and summer. The safety benefits of de-icing salts compel us to live with browning trees.
I have grown fruit trees here in Flagstaff for over 20 years but even though the trees look fine, I rarely get any fruit, except in 2005 when the trees were loaded. What am I doing wrong?

The problem with fruit production in the high country is cold night-time temperatures in the spring. Though many fruit trees are winter hardy, the developing fruit buds and flowers are sensitive to frost damage. Newly opening buds can usually withstand temperatures in the mid 20’s, but the blossoms of practically all fruit trees will be killed if the temperature drops below 24oF. When a heavy frost is expected, covering the trees may sometimes prevent bud or blossom injury though that’s only practical with dwarf cultivars. To increase the odds of getting a fruit crop, try growing later-flowering apples and plums rather than peaches and apricots that flower earlier and are therefore more likely to suffer from frost damage.

I recently saw a newspaper advertisement for the royal empress tree. The ad claims this hardy tree will grow 12 feet in one year, has fragrant purple flowers, tolerates any soil, and will grow almost anywhere. Our lot has no trees to speak of so we are desperate to plant some fast-growing trees. Is this tree too good to be true?

If an advertisement sounds too good to be true, it probably is. The royal empress tree (Paulownia tomentosa), also know as princess tree, is an exotic from China, introduced in the United States nearly 150 years ago as a landscape tree. Growing quickly, it litters, is messy, its wood is brittle, and only its root system is hardy. The weedy, aggressive tree has yet to invade the southwest but is considered an invasive exotic in many states. A noxious problem in many eastern states, it invades riparian areas, disturbing and displacing native species as a quickly growing nuisance.

When plants are featured in slick newspaper ads, beware! Research the plant before ordering. Caveat Emptor.

Hattie Braun is the coordinator for the University of Arizona Cooperative Extension’s Master Gardener Program and a Master Gardener. Dana Prom Smith, a Master Gardener volunteer and coordinating editor of the Master Gardener Column, can be contacted at stpauls@npgcable.com.