Gardening Help – Desert Botanical Garden

It's still relatively warm out, but October is the month to start preparing plants for the winter season. The idea is to encourage the slowing-down of growth so leaf and stem tissue will toughen and be more resistant to frost damage. Stop fertilizing and gradually begin cutting back watering frequency to achieve this.

Be sure to keep a field guide handy to identify all the butterflies and caterpillars in your fall garden. If your landscape isn't a-flutter with many types of winged beauties, you probably need to start a shopping list for the plant sales that are coming up. Don't forget to accommodate the hummingbirds, too.

Desert Milkweed queen
(Asclepias subulata)

Bloodflower (Asclepias curassavica) queen

Bloodflower (Asclepias curassavica) monarch larva

A must have for the autumn Queen and Monarch butterflies is milkweed. Native Desert Milkweed (Asclepias subulata) and Pineleaf Milkweed (A. linaria), as well as non-native Bloodflower (A. curassavica) will provide nectar for the adults to sip and foliage and flowers for the caterpillars to munch. These and so many other butterfly and hummingbird plants should be available at the Garden Plant Sale this month!

This is the perfect month for getting most plants into the ground. Since growth is tapering off and days are getting shorter (fewer hours of intense sun!), plants won't be as stressed above-ground. Warm soil temperatures will trigger new root development almost instantly. With root establishment beginning, fall-planted material has a jump on things when next summer's high temperatures roll around. Spring-installed plants may have to face 100º F temperatures within a few weeks of planting, which doesn't allow for much root development. The exception to the fall planting rule would be frost-sensitive plants. Unless you can adequately protect them from cold temperatures it might be better to add tender plants to your garden in the spring. Some plants such as Chaparral Sage (Salvia clevelandii) and lavenders (Lavandula spp.) establish much better in the fall. They can be too easily overwatered and rot when planted in the spring.

If you want to enjoy vibrant spring colors in your garden, plant your annual wildflower seed this month. See our Good Growing Guide "Planting Desert Wildflowers" for all the information you'll need to get them growing. Plant our native Desert Chia (Salvia columbariae) wildflower now and following the spring bloom of tiny purple flowers you can harvest the seed that is edible.

Desert Chia (Salvia columbariae)

Mizuna

Mostaza Roja, Red Kale

Artichoke

October is also the month to get the bulk of your cool season vegetable garden planted. If you like spicy flavors, try some of the mustard greens such as Mizuna and Mostaza Roja. Not only are they tasty, but they add exciting color and texture to your garden. Red Kale and Bright Lights Chard or Red Chard are colorful as well. Fava Beans add higher-reaching beauty, but need a longer period to mature. Place them where they won't conflict with spring planting next March. All of these can be direct seeded where they are to grow for the season. Artichokes are perennial plants, so locate them where they can grow for some years to come. Remember – your fall and winter garden needs to receive direct sun all day.

Desert Four O'clock
(Mirabilis multiflora)

Desert Four O'clock seed
(Mirabilis multiflora)

Marvel of Peru
(Mirabilis jalapa)

Collect seed that is ripening on four o'clocks. Native species, such as Desert Four O'clock (Mirabilis multiflora) and Long-flowered Four O'clock (M. longiflora), as well as non-native Marvel of Peru (M. jalapa) are all loaded with seed at this time. In a month or so they will all die back to their underground tuber for the winter season. Milkweed seedpods are plumping. Collect the pods just as they turn a pale green or tan color before they dehisce (split open) if you want to save the seeds – otherwise the seeds will float away on their fluffy parachutes. If the Pipevine Swallowtail caterpillars haven't eaten the developing seedpods on your native Pipevine (Aristolochia watsoni) catch them as they begin to split open. Once totally dried, you can store your seed for planting next spring.

Desert Milkweed (Asclepias subulata) seedpod

Pipevine (Aristolochia watsoni)pipevine swallowtail larvae back

Pipevine (Aristolochia watsoni)

Pipevine (Aristolochia watsoni) seedpod

You may notice birds, groundsquirrels, squirrels or other forms of wildlife enjoying ripening seed in your garden. Many animals are starting to put on their winter fat layer so leave as much seed for them as possible, and enjoy the excuse to leave a little "litter" in the yard.

Summer shade protection should be removed, and don't forget to adjust your irrigation schedule!

With temperatures lowering (but before it gets cold!) October is an ideal time to approach major pruning of your desert trees. Day length is shortening and the angle of the sun is lower so risk of sunburn is considerably decreased if you must prune a lot, but keep in mind the rule that no more than one quarter of the canopy should be removed in a season. If tree limbs need to be lifted for activity below, or if thinning is necessary, gather your clean sharp tools (no electric trimmers or chainsaws, please). This is also the month to give your established desert trees a final deep soaking for the season, then back off watering for the winter.

Gardening Calendar Archive

Garden Meetings

Arizona Native Plant Society
Tuesdays | 7-9 p.m. | November 11, December 9, January 13 and February 10 | Webster Auditorium Everyone is welcome. The Arizona Native Plant Society provides information about, fosters an appreciation of, and helps protect Arizona’s native plants. The Phoenix chapter emphasizes Sonoran Desert plants. Call Doug Green at 480-998-5638 for more information.

Central Arizona Cactus & Succulent Society
Sundays | 2 p.m. | November 16, Webster Auditorium / January 25 and February 22 | Dorrance Hall. Everyone is welcome. The Central Arizona Cactus and Succulent Society encourages the appreciation, study and growing of cacti and other succulents. Each meeting features a program about aspects of these fabulous plants. Call Judy Braun-Brody at 480-481-8129 for more information.

Central Arizona Butterfly Association
Saturday | November 8 | Meeting at Desert Botanical Garden | End of year get-together

Maricopa Audubon Society
Tuesday | 7:30 p.m. | January 6, February 3, March 3, April 7, September 1, October 6, November 3, December 1, 2009 | Dorrance Hall | Everyone is welcome. Call Laurie Nessel at 480-968-5614 for more information.