Answer: Landscape design is beyond the scope of this Q&A, but I?ll give you some ideas to consider and a good local resource. The most important things when choosing plants are determining what sun exposure (full, partial, shady) they will thrive in and how much space they need to grow to maturity (both vertically and horizontally), and then comparing that with what your landscape offers. In other words, you wouldn't want to put a huge sun lover in a tiny, shady location. This seems obvious, but many people forget it when they go to the nursery and are confronted by all sorts of beautiful plants. Analyze your site and think about what you want from plants (color, shade, cut flowers, bird attraction etc.) then choose plants that fit that situation. It sounds like you've started doing that, and you have selected a few very colorful, well-adapted plants. So, your next step is to determine if you have a sunny exposure (they all like full sun, 6 to 8 hours daily) and sufficient space for them to grow without having to cut them back, which eliminates the flowering and ruins their natural shape. Contact the Phoenix City Water Conservation Department for a free copy of Landscape Plants for the Arizona Desert. It is a color guide listing more than 200 low-water-use plants, along with their size, and other characteristics. Plants described can be transplanted in native soil without amendment.
Vegetables are a different matter. They need highly improved garden soil, or to be grown in containers. Almost every type of vegetable will grow there, but you need to know when to plant them. There are two growing seasons, a cool and a warm season, when different crops thrive. I suggest preparing your soil by adding lots of compost and just get it ready for the cool planting season, which starts around late September or so with plants growing through April/May. The warm season planting starts in Feb/March and plants go until the heat, or some go through the summer. Right now (late May), okra, blackeyed peas and melons can still be planted. A rule of thumb for determing when to plant is that cool season crops are those which you eat the stems, leaves, and roots, such as greens, carrots, beets, onions, etc. Warm season crops are those which you eat the fruits, such as tomatoes, melons, peppers, etc.
To improve your soil, incorporate plenty of compost. In sandy soils, compost improves soil fertility, water and nutrient retention. In clay soils, it improves fertility and drainage. Add a 4-6 inch layer of compost and incorporate it about 12-18 inches deep. You can use manure if it is well-aged (6 months) or you won't be planting until it has lost it's heat and decomposed. Each planting season, add more compost. Incorporate a balanced fertilizer (e.g., 10-10-10) or add organic fertilizers such as fish emulsion, bone meal, and seaweed/kelp. Follow package instructions.
As salts accumulate in clay soils, they impede water penetration. Gypsum is a soil amendment that helps sodium be dispersed and leached beyond the root zone. With our high pH soils, it isn't really possible to reduce the pH significantly or permanently. The addition of organic matter reduces it temporarily on a localized basis. Soil sulfur can do the same. Sulfur also acts the way gypsum does (but uses a different set of chemical reactions), so it isn't necessary to add both.
After planting, add a 1-2 inch layer of mulch. Mulch is great to help retain soil moisture, reduce weeds, and as it breaks down it provides nutrients to the soil. Any organic matter can be used as mulch. Try compost, bark, wood chips, straw, or pine needles. As it breaks down, dig it into your soil and add more.
The warm season starts with planting in mid to late February. Some plants will make it through the summer's heat; others will end their growth when the heat arrives in May or June. A rule of thumb for cool-season vegetables is that we eat parts of the plant itself, such as leaves (lettuces/greens), stems (kale, broccoli and other cole crops) and roots (beets, carrots, turnips, onions). (In the warm season, we eat the seeds and fruits (tomatoes, peppers, cukes). The major exception is peas. Although we eat the seeds, we plant them in the cool season.
For info on butterfly planting, please check out the June 28, 2001 Southwest Garden Report for the National Gardening Association at http://www.garden.org/regional/report/arch/inmygarden/320
If you have other questions, please send them individually to the Q&A site and we'll be happy to help you with your desert gardening!
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