The time of year is another important consideration when you plant a tree or shrub. Spring, summer and fall can all be appropriate planting times, as long as you take into account the impact of each season on plant growth. In many parts of the country, the cool weather, high humidity, and abundant rainfall of spring make this a particularly good time to plant. In summer, warmer temperatures promote growth but also increase a plant’s demand for water, so if you decide to plant at this time, choose a plant that has been well watered at the garden center, and irrigate it as needed after planting. Fall planting also has advantages – cooler air temperatures reduce the demand for water while the lingering warmth of the soil encourages rapid root growth. Take care, however, to allow your transplant enough time to become established before winter sets in.
The key to watering trees and shrubs is to water them slowly and allow the water to soak deep into the soil with no runoff. You can’t really do that standing there with a hose in your hand. I recommend drip irrigation systems whenever possible. They conserve moisture, while minimizing the liability of over watering. Since you don’t wet the foliage, you don’t encourage leaf diseases. The key to using drip irrigation is to water thoroughly, then allow the soil to dry moderately before watering again. As mentioned above, placing mulch over the drip system helps slow evaporation of moisture from the soil.