Planting Summersweet

Summersweet (Clethra alnifolia), also called the Sweet Pepperbush, is a moisture-loving perennial shrub. While Summersweet can be planted in a variety of different soil types, its need for consistently moist soil should be taken into consideration. Given the right lighting, adequate soil moisture, and correct planting, this summer-bloomer will provide ample, aromatic blooms to help usher in fall.


What You Need To Plant Summersweet

  • Shovel
  • Compost or manure
  • Garden spade
  • Good location
  • Water source
  • Mulch

Where to Plant Summersweet

Choosing the right spot for Summersweet will depend on the variety and its lighting needs. Summersweet is unique because it can bloom in relatively shady spots. Summersweet can grow in sandy to clay soils, making it an ideal plant for marshy spots or near a pond or stream. When planted in clay soil, amend with compost or soil conditioner to improve drainage. Summersweet prefers slightly acidic soil, so amend the soil accordingly. 

When planting, dig a hole at least twice the width and equal depth as the root ball. Place the root ball into the soil so that the top is level with the ground. When backfilling the hole, tamp down the soil lightly to provide stability and remove air pockets. Once planted, water deeply, thoroughly saturating the root ball and soil around it. Add 2-3 inches of soil around Summersweet to aid in moisture retention. 

Summersweet Spacing

Summersweet has the ability to spread up to 7 feet wide depending on the variety. For this reason, choose a spot that has plenty of room, at least 3 feet on either size from other plants and structures. Summersweet spreads via suckers, or new trunks that emerge from the roots, which can be pruned to limit its spread. If you are looking to create a low hedge, allow these suckers to grow.


Steps To Plant Summersweet

Step 1 - Choose a spot with plenty of room, light, and access to moisture. 

Step 2 - Dig a hole at least 2-3 times the width and the same depth as the root ball. Amend the removed soil with manure or compost if necessary to provide adequate moisture retention and drainage. 

Step 3 - Place the root ball into the hole and add soil back in around it, holding the shrub in the center to make sure it is planted straight. Tamp down soil around the root ball lightly to remove air pockets while still allowing water to permeate and the roots to grow. 

Step 4 - Once Summersweet is planted, water deeply, ensuring water reaches the entire root ball and the surrounding soil. Water again when the soil surface has dried out slightly.

Step 5 - (Recommended) Add 2-3 inches of mulch around the base of the plant to help the soil stay moist. 

When to Plant Summersweet

The best time of year to plant Summersweet is in the spring, giving the shrub a whole growing season to adjust to its new location and become established. Ideally, plant shrubs in the early morning or evening, avoiding the hottest parts of the day that may cause the plant stress. If planting in the summer is necessary, be sure to water Summersweet prior to and immediately following planting, never allowing the roots to dry out completely. 

Transplanting Summersweet

Summersweet will do best when transplanted in the spring. To dig up Summersweet, use a sharp spade to loosen the soil around the root ball, which extends to the plant’s width just below where the branches end. Dig down deeply to include as many roots as possible. Continue prying up the roots until the entire plant and root ball can be removed from the soil.

Transplant Summersweet into a new hole that is at least twice the size of the root ball. To reduce stress, do this process in the early morning or evening when temperatures are lower and water the plant immediately after transplanting.

Summersweet spreads through suckers under the soil. These suckers can be removed once they have their own root system and replanted to become their own plant. Simply use a sharp spade and dig around the sucker, removing the roots and surrounding soil. Replant into a new location, watering immediately. 

Propagating Summersweet can be done via stem cuttings. In early summer, cut 3-4 inches of softwood stem and plant into a pot with potting soil. If taken later in the year, dip the cuttings into a rooting hormone to aid in root growth. Keep the soil moist and the area humid by placing a plastic bag over the cuttings. 

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 Author Lynn Gusman - Published 1-13-2023