Pruning should be done to maintain plant health (remove dead, damaged or diseased portions, cross branching, etc.), to highlight the “natural” shape of the plant, to train a young plant, and to eliminate hazards. Excessive or heavy pruning causes significant stress to trees and shrubs. The best practices are to prune the least amount necessary and prune for legitimate reasons. How much to prune depends on the size, species, age, as well as your intentions. Two good principles to remember—a tree or shrub can recover from several small pruning wounds faster than from a single large wound and never remove more than 25% of the canopy in a year.
Lightly prune native and desert-adapted trees to prevent breakage during the summer thunderstorms in July and August if needed. Do not prune excessively as this will expose the tree trunk to the blazing sun causing it to sunburn.
Pruning newly planted trees is not recommended and, in fact, can be detrimental. However, at planting time prune broke or torn and diseased branches. Save other pruning activities for the second or third year. For more information on developing a healthy tree visit www.treesaregood.org
Continue to deadhead herbaceous perennials such as Desert Marigold (Baileya multiradiata), Chocolate Flower (Berlandiera lyrata), Texas Blanket (Gaillardia pulchella), Red Sage (Salvia coccinea), Mealy Cup Sage (Salvia farinacea), and Tickseeds (Coreopsis spp.).
Prune your cacti if necessary to maintain size, for propagation or to remove a damaged or diseased stem; prune at joint or segment. Use a sharp, clean pruning tool and spray tool periodically with a 70% alcohol solution to prevent infection. If the pruned stem is to be used for propagation, allow the cutting to dry out for a week before planting.
Continue to prune spent flowering stalks from Hesperaloes (Hesperaloe spp.), Agaves (Agave spp.), Yuccas (Yucca spp.), and Aloes (Aloe spp.).
Prune flowering stalks after seeds have ripened on Penstemons (Penstemon spp.), Globemallow (Sphaeralcea ambigua), Golden Columbine (Aquilegia chrysantha), and Brittlebush (Encelia farinosa). Shake pruned stalks to disperse seed in selected garden areas or collect seed in a paper bag to be planted in fall. You can also allow your seed to fall to the ground naturally thus providing a food source for many seed-eating animals.
Most native and desert-adapted plants in the landscape do not generally require fertilizer as they are adapted to our soil conditions. In most cases, fertilizers are generally applied to prevent deficiencies. If fertilizers are needed, one application for the year is usually sufficient. The best time to fertilize landscape plants are in March, April or the early part of May.
We do not recommend fertilizing your desert-adapted landscape plants during the summer months. Fertilizing will cause excessive, luxuriant growth that requires more water and new growth are too tender to take the excessive heat and sun exposure. Wait until next spring to fertilize, if needed.
For more information on fertilizing and plant deficiencies go to the University of Arizona Cooperative Extension Publications.
Periodic fertilizing may be needed for plants in containers as nutrients in the soil will have diminished over time. Always follow directions on the label.
Continue to fertilize your warm-season annuals and herbaceous and woody perennials in containers if necessary.
Cacti and warm-season succulents in containers should be fertilized at least once during the month depending on the type of fertilizer used. If using a slow-release granular fertilizer for your cacti and succulents in containers, fertilize in late March and again in July. Do not fertilize any winter-growing succulents such as Succulent Geraniums (Pelargonium spp.), Ice plants (Malephora spp., Drosanthemum spp., Cephalophyllumspp.), Living Stones (Lithops spp.) and crassulaceous plants (Kalanchoe, Cotyledon, Echeveria, Dudleya) as they are summer dormant.
Continue to fertilize your vegetable and herb garden as needed.