Following the long winter months, many gardeners are eager to start planting again. In some cases, you can begin planting even before the weather warms. Other plants need to be protected until temperatures rise. But, before you grab your shovel, equip yourself for success by learning the optimum time to plant-based upon plant type. Here’s a guide to get you started:
Annuals
Though some annuals are hardier than others, in general, these tender plants cannot tolerate freezing temperatures. While you may see summer annuals hit the garden center in March, it is best to wait until the average final frost date for your area before setting annuals in the garden.
Perennials
Most perennials live for many years in the garden and can survive winter through dormancy. A few perennials are evergreen, such as hellebores and Marc Anthony® Liriope, while others die back to the ground each winter. Perennials can be planted in the fall or early spring. In locations experiencing very hot summers, fall is the ideal time to plant perennials, as root growth will continue in soils above 40 degrees F, helping plants establish before the heat of summer.
For spring planting, the earlier the plant is established the better it can withstand hot summer temperatures. Container plants that are grown and stored outdoors can be planted as early as mid-March when you start to see other perennials in the garden come to life. Perennials raised in a greenhouse are not acclimated to winter temperatures and should be planted just after killing frosts have passed.
Fall planting should be completed at least six weeks before freezing weather is expected. This allows plants time to establish roots before winter.
Trees and Shrubs
Fall is generally the best time to plant container-grown trees and shrubs, giving plants a long establishment period before summer temperatures arrive. Avoid fertilizing and pruning fall-planted material as these practices encourage new growth that can be damaged when temperatures drop below freezing.
Of course, there are exceptions to every rule. Broadleaf evergreens such as holly and camellia are better planted in spring. One of the main reasons fall-planted broadleaf evergreens fail is due to winter water stress. Evergreen foliage is exposed to dry winds all winter long and continues to lose water. Spring planted evergreens have a full growing season to develop a strong root system that can better compensate for winter water loss.
