When planting in the summer, soak the plants in their containers before planting to make sure the potting media is wet. After planting, soak the area where the root ball was planted and the surrounding soil. The plant will need at least an inch of water, more if the soil was already dry. Continue to water deeply every four to seven days. Plants will dry out faster in hot and windy conditions. It can take up to 8 weeks for roots to extend beyond the container media and out into the soil, so be sure to water both the original root ball and the surrounding soil during that time. Container media tends to dry out more quickly than soil, so account for that in your watering. Usually about five to seven weeks after being planted new foliage begins to develop, signaling the plant is becoming established. Start to back off on watering, but keep an eye on the plant during dry spells.
The best way to check soil moisture is to push a screwdriver into the soil. If it comes back up with moisture on it, wait a few days and check again. If it’s dry or difficult to push into the soil, water deeply. Water needs to penetrate the soil surface and percolate into the root zone of the plant.
Check new trees weekly. Fill a 20-gallon watering bag, or run a hose at a trickle on the root ball of the tree for about 30 minutes, longer if the soil is very dry or the tree is large. Be sure to move the hose to make sure the whole root ball is getting water.
Trees that are established (planted three to five years ago) in lawn areas may be getting enough water from irrigation. It’s best to check the soil every couple of weeks during the summer to make sure the water is moving past the root zone of the lawn and into the tree’s root zone. If the soil is dry, use the watering methods described above.
Shrubs & Perennials
Water new plants deeply every four to seven days, about an inch per week including rainfall. If your plants are in their second or third season, they may not need this much water. Most shrubs and perennials can survive on our average rainfall. Five inches of rain during June, July, and August is enough for many well-adapted plants.
In containers: water daily during warm weather to establish. Use a screwdriver or your finger to check moisture two to three inches below the soil level. Keep in mind 4.5” or small 6-pack plants don’t have deep root systems at the beginning of the season, so it’s not necessary over-saturate your container. Shallow root systems will not be able to take in a large volume of water and can begin to rot. As the plants grow and the roots begin to fill the container, increase volume and frequency as needed. Most hanging baskets will need to be well soaked at least once a day in the heat of the summer.
In the ground: water daily in warm weather to establish. In general, once new growth begins to emerge water less frequently but with more volume.
Because annuals are chosen for their seasonal color rather than hardiness to our climate, and the wide range of annuals available, water requirements will vary greatly depending on the type of annual, soil quality, and the amount of sun or shade. Please consult with our annual specialists for the requirements for your site.
Turf needs about an inch of water a week. It’s best to apply this amount in intervals. Try running sprinklers three times a week, watering a third of an inch each time. Mow higher for more drought-resistant grass. Remember to water early in the morning to prevent problems with fungus.
Water Conservation in the Landscape
Water early in the morning
This helps prevent evaporation from heat and wind, and prevents fungal diseases from forming overnight on damp leaves.
Encourage healthy root systems
Always water deeply and then allow the plant to dry out between waterings to encourage the development of a strong root system. Plants that receive too much irrigation form shallow root systems compared to plants that are weaned from regular watering once they’re established. If we experience a period of drought that comes with water restrictions, these shallow root systems won’t be efficient enough to handle the abrupt drop-off of irrigation.
Use the water that flows through your landscape more efficiently.
City drainage systems have been designed to move storm water out of town as quickly as possible. This means that when we have severe storms that drop inches of water in a few hours, that water isn’t getting into the soil to be used by plants. Hard surfaces and turf that has been mowed short speed up the flow of runoff rather than absorbing it into the soil. This fast-flowing water collects pollutants from pavement and chemicals from lawns and causes water quality problems downstream. New solutions include perennial plantings like bioswales and rain gardens that slow down the flow of water to allow it to be useful rather than a waste product.
Choose water-wise plants
Select plants that can survive on average yearly rainfall. Deep-rooted plants like grasses, natives, and their cultivars not only find water resources deeper in the soil during drought conditions, they also create pathways for water to seep into the ground rather than running off into the sewer system.
Cover for more than aesthetics
Mulch, leaf litter, and ground covers can help shade soil and prevent loss of moisture. Rock increases heat above the ground and around the roots.
Allow lawns to go summer dormant
Fescue lawns cans survive on about an inch every two or three weeks. Bluegrass can survive on an inch every week and a half. This will not support a lush, green lawn, but the plants will green up again when the weather cools in the fall.