As the weather warms, plant water needs will increase. Now is the time to adjust your watering schedule for the summer. Observe plants regularly for signs of water stress. Some signs to look for include: wilting, curling leaves, yellowing or falling of older leaves, and dead stems or branches.
The amount of water and watering frequency depends on many factors. These include soil type, weather (temperature, humidity, rainfall, etc.), microclimates, cultural practices, plant size and species, and whether newly planted or established in the landscape (two years or more). Below are general guidelines to help you determine how much and how often to water your landscape and container plantings to keep them healthy when rainfall is lacking.
Established native or desert-adapted trees and shrubs should be watered at least once to twice monthly. Water at least 3 feet deep for your trees and 2 feet deep for your shrubs. Always allow the soil to dry out between each irrigation cycle.
Natural rainfall may be adequate for most well-established cacti and succulents. However, if rainfall is insufficient, water may be needed at least once to twice during the month of May. Water your cacti and succulents to a depth of at least 8-12 inches. Always allow the soil to dry out between each irrigation cycle.
Established herbaceous perennials, groundcovers, and vines should be watered every two to three weeks and at least 1 foot deep. Always allow the soil to dry out between each irrigation cycle.
Wait a week after planting your cacti and succulents before watering to minimize the chance of rot. After the initial irrigation of your succulents, allow the soil to dry out and water every 10-14 days. Cacti need to be watered once more after initial watering during the month but allow the soil to dry out between watering.
Newly planted native and desert-adapted trees and shrubs may need to be watered more frequently until established. It can take up to 3-5 years for trees and at least 1-2 years for shrubs to become established in the landscape. After planting your trees and shrubs, they should be watered immediately and the moisture monitored for the next few days to keep the root ball from drying out. Schedule your irrigation cycle for trees and shrubs every 7-10 days during the month. Allow the soil to dry out between irrigations and always water deeply, 3 feet for trees and 2 feet for shrubs.
Newly planted native and desert-adapted herbaceous perennials, groundcovers and vines should also be watered immediately and for the next few days to keep the root ball from drying out. Schedule your irrigation cycle for herbaceous perennials, groundcovers, and vines for at least once to twice weekly and to a depth of 1 foot. Allow soil to dry out between watering.
Agaves and other succulents (Aloe spp., Pachypodium lamerei, Beaucarnea recurvata, Pedilanthus macrocarpus, Euphorbia spp., Gasteria spp.,Haworthia spp.) in containers should be watered at least once to twice this month. Cacti in containers should be watered at least once this month. However, cacti and succulents in small containers may need to be watered more often especially cacti and succulent seedlings.
Keep an eye on your warm-season annuals and herbaceous perennials in containers. Water them at least once to three times weekly.
Herbs may need to be watered every 3-5 days and vegetables need to be watered every 2-3 days. Water your herb and vegetable plants to at least a foot in depth.