Clethra
Summersweet, White alder
- Height × spread
- 1.2m – 2.5m × 1m – 2.5m
- Position
- Part shade
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
The often overlooked 'Summer sweet' generally flowers in the autumn, when the sweet fragrance of its flowers is an unexpected treat. Clethra alnifolia takes on yellow autumn colour as well. There are numbers of pleasing cultivars that deliver flowers in variable shades of pink. Forms of Summer sweet come from different parts of the world, Japan yielding Clethra barbinervis, whilst Madeira delivers the somewhat tender Lily of the Valley tree (Clethra arborea). All these shrubs have a suckering growth habit and like acidic or neutral soil.
- Flower colour
- Pink, White
- Foliage colour
- Green
- Variegated
- No
- Scent
- Yes, some varieties
- Shape
- Oval
- Height
- 1.2m – 2.5m
- Spread
- 1m – 2.5m
- Season of interest
- Summer, Autumn
- Evergreen
- Deciduous
- Garden style
- Seaside garden, Scented garden
- Sun or shade
- Likes part shade, likes light shade
- Soil type
- Loam (normal)
- Soil pH
- Acid (ericaceous), Neutral
- Drainage
- Moisture retentive soil, Damp and wet soil
- Winter hardiness
- Varies, most are hardy
- Borders & containers
- Borders
- Use for
- Hedge, Structural
- Hazards
- No
Spring
Spring - late · Outdoors
Feed with slow release fertiliser
Apply a general purpose slow release fertiliser, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)
This is a simple way to provide a nutrient boost as a single annual procedure.
Spring - late · Outdoors
Feed with sequestrol
If plants are acid loving and grown in soil with little acidity, or in a container, or are watered with limey tap water an annual feed with sequestrol (iron chelate) is highly beneficial. Follow guidelines on the packet. Will also 'blue-up' hydrangeas.
For hydrangeas that have good blue flowers in acid soil, this product can be used with alkaline soil to turn the flowers blue. This is most effective when the soil is neutral or just slightkly alkaline.
Spring-Autumn · Outdoors
Water to keep the soil moist
For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.
Without regular watering some plants never fully regain their beauty.
Winter
Winter - mid-late · Planting
Prune during dormancy
While dormant, prune the plant to keep it attractive and healthy by removing dead branches, removing branches that cross or rub each other and those which spoil its appearance.
The plant is encouraged to develop a pleasing shape by removing deviant or dead growth. It is much more likely to remain healthy if branches that rub, or can rub each other are removed, since the rubbed spots can be places where disease is introduced.
Found in
More Clethra
Clethra alnifolia 'Hummingbird'
Sweet pepper bush, Summersweet
Clethra alnifolia
Sweet pepper bush, Spiked alder
Clethra alnifolia 'Paniculata'
Sweet pepper bush, Spiked alder
Clethra alnifolia 'Rosea'
Sweet pepper bush, Spiked alder
Clethra alnifolia 'Ruby Spice'
Sweet pepper bush, Summersweet