Urban Gardening: How to Start Your Trees and Shrubs Right
How well your tree or shrub grows in its first year in your urban garden depends on a number of factors. Planting the right tree in the right location and selecting a variety that’s adapted to your area are probably the two most important pieces to the puzzle. But after your tree or shrub is safely in the ground, you can help keep it healthy by following these basic guidelines:
Keep watering. Your young tree or shrub needs a constant supply of water throughout the growing season to keep growing well. If your native soil is mostly heavy clay and doesn’t drain quickly, you need less water than if your soil is sandy and drains fast. Water once or twice a week if you don’t get a soaking rainfall.
When you water, really soak the soil instead of just lightly sprinkling the ground. Frequent light watering encourages the roots to stay close to the soil surface to get the water, but you want them to grow deeper into the soil. After all, if they stay close to the soil surface, your tree or shrub will be more prone to drought stress when conditions are dry.
You can always check the soil around your plant to see whether it’s dry. Dig down about 6 inches into the soil. If it’s dry at 6 inches, then water. Most trees and shrubs need 1 to 3 inches of water a week. To visualize how much water that is, consider this: Five gallons per square yard is about 1 inch of water.
Treegators are plastic bags that you fill with water and place around newly planted trees or shrubs. They have small holes in the bottom and slowly drip water into the soil around the plant, keeping it moist. They’re popular in public areas where tree crews don’t have the time to water the trees regularly. When the bag is empty, simply fill it with water again for another dosing.
Use Treegators only on new trees and shrubs because they drip water just around the planting hole and don’t encourage older tree roots to venture into the native soil.Credit: Illustration by Kathryn Born.
Hold off on fertilizing. Although new trees and shrubs do need a fertile soil to get off to a good start, hold off on adding any fertilizers until the second year. Let the roots get established and the tree or shrub adjust to its new home before adding any more fertility to the soil.
Replenish the mulch. In warm summer areas, the bark mulch or pine straw used around trees and shrubs may decompose by the end of summer. You can add more mulch in fall as long as you don’t increase the mulch depth to more than 4 inches overall and you keep the mulch away from the tree trunk. In cold winter areas, mulch helps insulate the roots, protecting the plant.
Add some protection, please. If you plant an evergreen tree or shrub in fall in a cold area or if that evergreen is marginally hardy for your area, protect it by wrapping burlap around the plant in late fall. Pound four stakes around the plant and wrap the burlap to protect the bark and branches from the cold winter winds. Remove the burlap wrapping in spring.