Unlike other parts of the country, in the desert September is not the end of the year’s only growing season, but the beginning of yet another. This is the time to enjoy the transition to fewer triple-digit temperatures, lower humidity, migrating songbirds, and more pleasant hours in the outdoors. Now what to do in the garden.
Geraniums may begin to look weary about now, so they can be heavily pruned. Trim just above a healthy side branch. The plants will not only appear fresher, but will produce new shoots and flowers for winter.
If roses are your choice, continue deadheading spent blooms and trim lightly. To stimulate flowering into fall, remove dead or damaged canes that may be growing from the rootstock. Remaining canes can be cut back by one-third. Keep plants well watered and fertilize regularly.
When growing iris, this is the time to divide the clusters. Dig and cut rhizomes into pieces with three fans of leaves. Cut back to 6 inches and clean away any damaged or dead leaves. Next, transplant rhizomes just deep enough to cover with soil.
A light application of water-soluble, high-nitrogen fertilizer will encourage new growth of any heat-stressed plants in the garden. Ammonium sulfate (21-0-0) is a cost-effective dry mix that, after scattering, should be watered in. Also available are powders and liquids that are to be diluted and poured around the plant base.
Keep all annuals and perennials watered on a regular schedule, and notice how quickly they recover with the coming of cooler fall temperatures.
Why not try planting a few spring-blooming bulbs this year? Among easiest to grow in the desert are freesia, narcissus, crocus, zephyranthes, allium and hyacinth. It is recommended to buy bulbs now while selection is best. Put them into a paper bag and store in the crisper section of the refrigerator away from fruit. Next month, when the soil has cooled, plant into a container or the garden.
As soon as daylight temperatures reliably remain below 100 degrees, vegetable gardeners can start to sow seed of lettuce, beets, chard, carrots, radishes, kale, leeks, kohlrabi, peas and turnips. Onion sets and transplants of broccoli, cabbage, cauliflower and Brussels sprouts can be planted when commercially available.
When planting herbs, raised beds or containers with organic potting soil are ideal. This is time to plant parsley, thyme, chives, cilantro, sage and oregano. Winter herbs prefer morning sun and grow best with regular applications of a complete, water-soluble fertilizer.
To the garden, September often brings strange looking caterpillars, noisy metallic beetles, butterflies of many colors and patterns, expanded quail families, hungry black cactus beetles, singing finches, chirping verdins, busy hummingbirds, and brightly colored grasshoppers … such a delightful place to end the summer!
Mary Kidnocker is a University of Arizona Master Gardener who lives in the Green Valley area. Her articles are featured weekly.