Ask Burton: The month of July certainly brings the heat, and it’s a challenge for newly planted shrubs, trees, and container plantings. So, this week, a simple heads up on watering – how to, how often, and simple things you can do to reduce the need for excessive watering.

New plantings need hose watering. The sprinklers will rarely be enough. Irrigation systems will wet the top two to three inches of our local clay soil at best, unless they run for truly excessive lengths of time. For established plantings, this is fine! Your trees and shrubs have spread roots over a broad area and can pull enough moisture from that soil depth that this is plenty. A newly planted shrub, on the other hand, tends to have a large top for a proportionally narrow root ball. That two-to-three-inch depth of soil just doesn’t hold enough water to keep the new plant happy in this much heat. Sprinklers can help you keep new trees and shrubs watered but should not be expected to get the entire job done. Water smaller shrubs by hand and really take your time to puddle the water around each one. Let the hose dribble slowly (you can set it down) over the root balls of larger shrubs and trees to saturate the whole root ball and the immediate soil around. Two good, slow soakings by hand per week on top of your sprinkler will water most new shrubs and trees well, but water more if temperatures spike.
Double-water dry containers. Container flowers and small shrubs will usually need daily watering in this much heat, but container soils have a nasty habit of shrinking when dry. This can lead to root balls which have shrunk back from the sides of your containers unless you’re careful! Once the soil has gotten that dry, only a fraction of your watering will properly soak into the soil – the rest will simply run down the sides of the container, and out the bottom. We recommend watering all the containers on your patio or poolside, then starting right back in at the beginning and hitting them again if they’ve dried out excessively. The first watering will plump the soil back out to rest against the sides of the container, and the second hit will thoroughly water the plants and soil.
Mulch, mulch, mulch! Mulch isn’t used just to dress up your flowerbeds – it’s quite functional. One to two inches of mulch over the soil of a bed or container will reduce water loss to heat and wind, keeping your plants far more comfortable. It doesn’t matter what type of mulch you use, so much as that you do use a mulch to cover the soil – any normal landscape mulch will do as long as it won’t float away.
For extra credit, Soil Moist. A polymer that absorbs water when it’s available and releases it once the soil around has dried enough to need it. This is best worked into the soil or worked into container mixes at planting. Soil Moist won’t let you go extra days between watering this time of year. But it can absolutely make the difference between a plant that’s been badly dried out, and one which just needs to be watered.