Illustration of a watering can with the text watering guide

Water is the most important thing you can do for a new plant. All newly installed plants need to be watered for the first year, and trees and shrubs need to be individually watered. A simple way to think about how long and frequent to water is to think about the size of the plant and its root system. There are many other factors such as the type of plant, location, sun and wind exposure, type of soil, and ground slopes among others, but we’re going to try and keep this guide as simple as possible.

The average tree we sell has a root system approximately 3’ in diameter. Compare that with a perennial groundcover where the root systems could less than 1” deep. In order to keep all plants appropriately watered they have different requirements. Trees benefit from less frequent, long, slow soakings. After all, the root system is 3’ deep into the ground. Due to this depth, it takes the moisture longer to evaporate and be used so we don’t need to water as much. With smaller material, the root systems are much shallower. This is one of the main reasons why we need to water more frequently with shorter time intervals. Remember we should water and treat each plant individually. All newly installed plants must be watered in thoroughly with a long, slow soaking by hand. Following are more specific guidelines to help with proper watering throughout the year.

Illustrated tree icon

Trees

We recommend a slow drip by a hose placed at the top of the root ball (next to the trunk). This enables the water to be absorbed directly into the root system. If the water is on too high it can run off of the root ball and water everything around the tree. To make sure the water is penetrating the root ball, dig down several inches and feel the soil. Also press on the root ball to check for moisture. If it is moist, watering can be cut back. If the soil is dry or crumbles, then increase watering slightly.

Shrubs

We recommend watering each shrub individually when first installed. This can be done either by slow drip or overhead watering by hand. If watering overhead, select a group of seven or so plants and cycle through them 3 to 5 times to ensure the water has time to penetrate the root system of the plant and not just run off around the plant. If an irrigation system is installed with proper settings, shrubs can be maintained through the system after initial watering.

Perennials, Annuals, and Smaller Plants

We recommend watering more frequently. This can be done overhead by hand.

Remember we should water and treat each plant individually. All newly installed plants must be watered in thoroughly with a long, slow soaking by hand. Following are more specific guidelines to help with proper watering throughout the year.

Seasonal Watering

Following are more specific guidelines to help with proper watering throughout the year.

SPRING

March, April, May

Depending on rainfall, plants normally do not need to be watered often in the spring season.

TREES
Trees most likely will not need any water during the spring months. If we are going through a drought or an abnormally dry spring, a long, single soaking (24 – 48 hours depending on tree size) could be enough to make it through the spring.

SHRUBS
Similarly, to trees, shrubs will most likely not need to be watered in the spring months. If we are going through a drought or an abnormally dry spring, shrubs may need to be watered once a month. If an irrigation system is running, shrubs should not need any additional watering.Perennials, Annuals, Smaller Plants Smaller plants may need water if we go through multiple weeks of dry weather. Because their root systems are shallow, it is easier for them to dry out. If they are under an irrigation system, they should not need any additional watering through the spring.

PERENNIALS, ANNUALS, SMALLER PLANTS
Smaller plants may need water if we go through multiple weeks of dry weather. Because their root systems are shallow, it is easier for them to dry out. If they are under an irrigation system, they should not need any additional watering through the spring.

SUMMER

June, July, August

This is the most important season to ensure your plants are receiving enough water. St. Louis can have extremely dry, hot summers.

TREES
At time of planting, water the tree (up to 3” tree) with a slow drip for 24 hours. If the tree is over 3”, the slow drip should be 48 hours. Time between watering after that will vary depending on your soil and if you have irrigation. Irrigation is usually not sufficient for a newly planted tree because of the large root system.Topsoil: If you have topsoil, check for watering once every seven days. During summer weather you will probably need to water every seven to 14 days depending on plant type/irrigation. To check

Topsoil: If you have topsoil, check for watering once every seven days. During summer weather you will probably need to water every seven to 14 days depending on plant type/irrigation. To check moisture level of the tree, dig down at least eight to 10 inches alongside the root ball, soil in root ball should be moist not powder dry before watering again.

Clay: Depending on the severity of your clay soil, check for watering every seven days. Clay tends to hold moisture for a longer period of time, so watering once every two to three weeks may be sufficient through the summer months.

SHRUBS
Irrigation in beds will help with shrubs. Newly planted shrubs may need additional water beyond what an irrigation system will give (you do not want to drown other plants). Check newly planted shrubs on a regular basis (about once a week) to get an idea how fast they are using water. Water #1 container plants different than a #5 container plants. There could be a 1 to 3 hour difference. (A small #1 container will dry out faster than a #5.) In beds without an irrigation system, soaker hoses work very well to water a large area at once. Group watering to the plant that needs the least amount of water. Individually water the plants that need additional water beyond the group to prevent drowning the other plants.

Perennials, Annuals, Smaller Plants
Smaller plants should be monitored every couple of days, if not daily when we are going through extreme summer heat. Additional overhead watering can help keep smaller plants alive through the summer months.

FALL

September, October, November

During the fall season, frequent watering is usually not needed because of the amount of moisture received in the fall. If it is a dry fall, the summer watering technique should continue but with further duration between waterings.

WINTER

December, January, February

Depending on rainfall and temperatures, plants normally do not need to be watered often in the winter.

TREES & SHRUBS
If watering is necessary, do so on a mild day (45-50 degrees) to allow the water to penetrate the soil and root ball. Follow slow drip method by placing a hose at the top of the root ball and letting it drip.

PERENNIALS, ANNUALS, SMALLER PLANTS
If watering is necessary, do so on a mild day (45-50 degrees) to allow the water to penetrate the soil. A light watering overhead should suffice to supplement the plants through the winter.

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