Pre-emergent Weed Control
Your yard has an initial application of pre-emergent applied to all areas covered by decomposed granite (DG), which helps prevent seeds from germinating. It will last only one growing season—pre-emergent should be applied a minimum of twice a year. Pre-emergent comes in liquid and granular form. Pre-emergent can be over-sprayed on desired plants with no ill effects. Ask your nursery professional for the best pre-emergent for your landscape. Weeds that pop up in your granite can be taken care of a couple of ways. One method is to physically remove them, including the root. This is the most effective when only a few weeds exist. Another method is applying a chemical control such as Round Up™ Spray. Spray on desired weeds, but don’t allow the chemical to contact any plant you want to keep.
Frost and Freeze Protection
Although Arizona has generally mild winters, night time temperatures can reach below freezing. Become familiar with your plant palette and understand which plants are frost-sensitive. Keep in mind that some trees and plants lose their leaves in the winter (deciduous). These deciduous species are not dead, just dormant. To help prevent frost damage, cover your plants with a large fabric (this can be linens or specific landscape tarps). DO NOT USE PLASTIC. When plastic is in direct contact with plant leaves, it causes more damage than not using anything at all. Also, it will help if you saturate the ground around the plants the night before frost is expected. If your plants do get damaged, don’t prune them, as the frost-damaged parts act as insulation to prevent further damage.
Leaves are yellowing
First, check the watering. Make sure plants are neither over nor under-watered. Bright yellow leaves generally indicate under-watering. Dull yellow leaves generally indicate over-watering.
Leaves are browning
Browning leaves can sometimes indicate under-watering. Check to make sure the plants are receiving water properly from the irrigation system. The emitter may be plugged, or the spaghetti tube may have come loose. Check for brown tips on the leaves. If the leaves are mostly green with brown tips and a yellow band between the brown and green, this is salt damage. The soils here are very salty. Water the ground around the affected plant/tree deep enough to flush out the salt build-up. If you noticed browning within two weeks of your last fertilization application, too much may have been applied, or not enough water was applied to help flush the fertilizer. Water the ground around the affected plant/tree deep enough to flush out the over-fertilization.If you haven’t fertilized recently (within the past 2-3 months) you may want to apply a water-soluble fertilizer.
Leaves are wilting
During the summer, even if plants are receiving adequate water, plants may wilt because of the heat. This is more common with non-native plants. Once the plants adapt, they will perk up. If the plants do not perk up, check your watering. During the rest of the year, check the emitters and your watering schedule.