Perennials

Water

• Irrigation is usually necessary to assist in the establishment of perennials. Also, one very deep watering per week is more desirable than numerous shallow waterings. Apply water early in the day using a soaking technique at ground level. Watering the foliage can cause diseases to be spread.

Soil

• Perennials planted in June or later in the summer do require initial care. The garden area should be prepared with humus or other organic matter, allowing for enhanced moisture retention. Newly established beds should receive four inches of organic matter per 12 inches of soil profile, to ensure good drainage and optimal root growth.
• Remember to mulch after planting, in order to promote moisture retention, retard weed growth and improve the overall appearance of the garden. (See Wagner’s Mulch Coverage Chart to calculate the proper amount of mulch for your garden.) Keep mulch away from the crown of the plant to avoid rot. Another way to prevent weeds is by using chemical weed preventers such as Preen before planting.

• June is the month to shear the tops of spring bloomers. This ensures a uniform and ornamental foliage effect for the remainder of the season. Grass shears can be used for this task. At this time, one should also cut back the foliage of the spring flowering
  daffodils and tulips that bloomed at least six weeks previously.
• Early-to-mid-June is a good time to cut back late season bloomers by half. This controls height and eliminates the need for staking. Perennials treated in this manner will mature at a shorter height and may flower slightly later than unpruned perennials. Throughout the summer season, plan to deadhead, or remove, spent flowers as the need arises. This practice will improve the appearance of the plant, eliminate an abundance of unwanted seedlings and promote a continued bloom period or later re-bloom.
• Some perennials multiply and grow larger each year, calling for an occasional division to keep them healthy. Other plants stay very much the same height and spread, and require little attention after planting. Dividing should be done in the spring, just as new shoots appear for plants that flower later in the season or in the fall for plants that flower in early spring.