First Rule…Do No Harm. If you are watering every day, this is harmful and as far as you can get from the ideal watering practice for your plants’ health and for growing in your design. Plus you will be accidentally training your plants to be shallow rooted and water hogs. One is not good for the plants and the other not good for your wallet. If this is how you have been watering for years and you want to change, let’s talk.
Newer Plant Material: I consider any plants that have not been through a summer to be a first year plant. Plants 2 or 3 years old are established plants. I typically have clients start watering first year plants every 2 weeks in April (depending on weather conditions in the Pacific Northwest). This can continue into mid-May most years but by the end of May new plantings should be getting watered once or twice a week. When we start having 80 to 90 degree weather, first year plants should be watered 2 to 3 times a week maximum, not every day. We want to manage the plants water needs with other methods besides over watering.
Don’t wait until you see signs of stress – it can be hard to get moisture back into clay soils once they dry out. Do you see leaves wilting, scorching, crumpling, or dropping? Here are some ways to save a stressed plant:
(1) In the evening, after the sun goes down, hose down the leaves, to cool them off. Or hose them down very early in the morning (before 8 a.m.). Never sprinkle leaves after 9 a.m. in sunny weather, this will create scorched (toasted) leaves and flowers.
(2) Cover your plants’ leaves for 3 days or less. Covering plants helps them conserve water loss. When not exposed to the sun, the cells in the leaves will close. And when closed, the leaf cells hold in the water which prevents evaporation. This conserves the existing water in the roots and leaves.
To cover the plant take a lightweight fabric (a white or light colored sheet is ideal) and attach it to the plant during the most extreme heat. I like to use black office clips on individual trees or shrubs. Or use rocks to hold the fabric down if you are covering an entire bed. Note: This is also an excellent way to protect a plant from drought stress after transplanting.
(3) In late summer when heat spikes up to 100 degrees you could add one additional watering per week. Check your soil a few inches down with your hand. If it’s still moist, watering is not the solution it’s the problem.
Established Plant Material: Plants 2 or 3 years old are established plants. If you have heavy clay soil you may need to water twice a week even in early summer. Apply the water slow and for a long period of time. If you have better draining soil, plantings may only need once a week watering. All plants will respond to sudden change in temperature, for instance mild early summer weather interrupted by 3 days of intense heat, you will see leaf droop or slight wilting. As soon as the intense heat retreats, the plants are fine and the leaves return to normal. The only way you will know if they need additional watering over and above your typical practice is if you check the soil. Remember, too much moisture and too much heat equals root rot. Remember first rule, do no harm.