Woods' Rose Courtesy of Clarence A. Rechenthin @ USDA-NRCS PLANTS Database

By Beverly Lehnhardt | Sedona.biz

Although you can plant all year round in Arizona, early fall is the time to do any last-minute planting of ‘green leafies’—any plants with green leaves. At this time they are still growing and will have time to send roots out into the soil, becoming well established before the weather turns too cold. If planted during the winter months, these plants do not send out roots, remaining pretty much as they are put into the ground. In this case, the colder weather is really hard on them and they may not survive. If given the opportunity to become established in the fall, they will ‘sleep’ the winter away, send out new growth in the spring and provide you with a plethora of beautiful blooms.

The Fall is also your last chance to give the plants their final fertilization of the year. You never want to fertilize during the winter while plants are dormant—that would be equivalent to having someone awaken you at 3:00 a.m. to force feed you pumpkin pie! The pie tastes great after dinner but not in the wee hours—as they say, timing is everything…

In Arizona, autumn is a great time to prune almost all bushes, especially roses, so they are ready to send out new growth in the spring. Proper pruning of roses not only encourages larger sized roses, but also helps create longer stems and more attractive bushes. You may want to do some research on pruning your particular type of rose bush or tree. Various types require different methods of pruning to produce attractively-shaped and prolifically flowering specimens.

Iris

This is also the only time to divide bulbs. Older, well-established irises especially need this division to provide you with gorgeous spring blossoms—irises should first be divided when they are two to three years old. Irises grow from thick, underground stems called rhizomes. To divide your irises, carefully dig up the iris clumps with a spade and cut the leaves back to 1/3 their original height. Wash soil from the rhizomes and roots with a hose and then cut the rhizomes apart with a sharp knife. Each division should have a fan of leaves, a healthy rhizome, and several large roots; discard all diseased or insect damaged sections.

To replant the irises, dig a hole large enough to accommodate the rhizome and its roots. Build a mound in the center of the hole; place a rhizome on top of the mound and carefully spread the roots in the surrounding trench. Space the rhizomes about 12 to 24 inches apart. Point each fan of leaves away from the other irises in the group. Cover with soil. When planted, the rhizome should be just below the soil surface; water each plant thoroughly. Transplanted irises will bloom sparsely the first spring but the plants should be in full bloom in the second and third years.

Fall is also a good time to replenish mulch in established beds by adding a one- to two-inch thick fresh top layer or to mulch new areas. Mulch is helpful in a variety of ways: it conserves moisture, helps keep the soil aerated by reducing soil compaction that results when raindrops hit the soil, reduces water runoff and soil erosion, helps maintain a more uniform soil temperature (warmer in winter and cooler in summer), and promotes the growth of soil microorganisms and earthworms. A two- to four-inch layer of mulch is adequate to prevent most weed seeds from germinating and should be applied to a weed-free soil surface.

The mulched area should include as much of the root zone as possible. For flower beds, mulch the entire area. For individual plants or trees, the mulched area should extend at least three to six feet out from the base of the plant. You should pull the mulch one to two inches away from the base of plants to prevent bark decay.

Lantana

Mulching will help protect flower beds and prevent the roots of many marginal plants such as Palo Verde, Sago Palm, San Pedro Cactus, Lantana, and Red Bird of Paradise from freezing. ‘Marginal plants’ are those known to tolerate winter temperatures at or slightly above the lows reached in this area. Therefore, they may need special care to survive our occasionally frosty nighttime winter temperatures. Many plants will grow back if only the exposed foliage is frozen; however, if the roots are nipped it is rare that the plant will recover. Bougainville is sold at many garden shops in our area; however, as a native of Brazil, this beautiful, sprawling shrub will only tolerate a low temperature of about 28 degrees. Many times we experience much lower nighttime temperatures than that, making it difficult for the Bougainville to survive here.

Now armed with information on how to prepare your plants for impending winter weather, you should enjoy the fruits of your labor next spring in the guise of prolific, healthy flowering plants and shrubs! 

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