Summersweet 'Ruby Spice'
Clethra alnifolia 'Ruby Spice' · Clethraceae
Upright spikes of deep rose-pink, strongly scented flowers that do not fade, in late summer, with golden-yellow leaves in autumn.
- Size
- 6 ft tall, 4 ft wide
- Zones
- 4 to 9
- Light
- Full sun to part shade
- Flowers
- Mid July to mid August
- Pets
- No toxicity recorded
- Job in a bed
- Anchor
A bed built around summersweet 'Ruby Spice'
The planner designed this bed around summersweet 'Ruby Spice' when this page was made: a 16 × 8 ft (4.9 × 2.4 m) English border in zone 6, part sun. It chose the other plants from the 708 that suit those conditions, and says below why summersweet 'Ruby Spice' stands where it does.
The plants
- 1 Summersweet 'Ruby Spice' × 1, pink
- 2 Stemless gentian × 24, blue
- 3 Mouse-ear coreopsis 'Nana' × 24, yellow
- 4 White mugwort × 4, cream
- 5 Siberian iris 'Caesar's Brother' × 5, purple
- 6 Foamy bells 'Sweet Tea' × 5, bronze leaves
- 7 Asiatic lily × 3, yellow
- 8 Camassia × 5, blue
Why this plant
- The bed's only structure. Shrubs and grasses keep their shape when the perennials die down, and it is the only one here.
- The only pink.
Why here
- Anchors a back corner. At 6 ft it is the tallest plant here, and the tallest close the ends of the bed, where they stand in front of nothing.
- A step in the back row. Next to white mugwort (5 ft): no two neighbours there are the same height, so the back steps up and down like a skyline.
- One plant, alone. A shrub is seen as an object, and needs clear ground around it.
Why now
- In flower for six weeks. From mid July to mid August.
- Fills a gap. For three of those weeks nothing else on the plan is in flower.
Planned as an English border: 9 of the 10 groups (90%) are drifts, longer along the bed than they are deep. Neither end outweighs the other: the visual weight is split 53 to 47, left to right. The front edge is finished with mouse-ear coreopsis 'Nana' and stemless gentian.
The planner's own design check: 9 Excellent, 7 Good, 1 Satisfactory.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where summersweet 'Ruby Spice' goes in a border
At 6 ft it belongs at the back of a bed. In the planner's ten height classes it is very tall (5 to 6½ ft).
Its job: anchor. A shrub that gives the bed permanent structure. Planted singly, as soon as the front edge is laid; everything else is arranged around it.
The best pink summersweet. It flowers in shade, in wet soil, in August, with scent: four things few shrubs manage at once. It suckers slowly into a clump.
- Scent in late summer
- Wet soil and rain gardens
- Flowers in shade
What to plant with summersweet 'Ruby Spice'
Plants recorded as good partners for it, and what each pairing does:
- Winterberry: its green leaves are a setting for the flowers, before and after; a low mound at the foot of its spires; happy in the same moist soil.
- Virginia sweetspire: flowers first, early June to early July, so the spot is never empty; happy in the same moist soil.
- Cinnamon fern: its green leaves are a setting for the flowers, before and after.
Questions about summersweet 'Ruby Spice'
Does summersweet 'Ruby Spice' need sun or shade?
Summersweet 'Ruby Spice' grows in full sun (6 or more hours of direct sun a day), part sun (4 to 6 hours of sun, including some afternoon sun) and part shade (2 to 4 hours of sun, mostly in the morning). It is one of the few that also put up with deep shade.
It wants soil that stays evenly moist, rich in organic matter, and plenty of water. It copes with soil that stays wet.
What zones does summersweet 'Ruby Spice' grow in?
USDA zones 4 to 9. It is hardy to zone 4, which means it survives winter nights down to about −20 °F (−29 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does summersweet 'Ruby Spice' flower in my zone?
In zone 5 it flowers mid July to mid August. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 4 | Mid July to late August |
|---|---|
| Zone 5 | Mid July to mid August |
| Zone 6 | Mid July to mid August |
| Zone 7 | Early July to early August |
| Zone 8 | Early July to early August |
| Zone 9 | Late June to early August |
Worked out from Hopkins' bioclimatic law: spring arrives about four days later for each degree of latitude north, and one zone is roughly two degrees. A warm spring or a cold one moves any garden two weeks either way.
How far apart should summersweet 'Ruby Spice' be planted?
3½ ft (100 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 4 ft (120 cm), so a group knits into one patch.
It grows 6 ft (180 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many summersweet 'Ruby Spice' plants do I need?
At 3½ ft apart, set out in staggered rows:
- 1 to fill 10 square feet (about 1 m²)
- 4 for a single row 10 ft (3 m) long
- 3 to fill a 4 × 8 ft bed on its own
In a mixed border, plant it as one, planted singly: it is the bed's structure, and everything else is arranged around it.
In the bed above, the planner used one in one group.
Is summersweet 'Ruby Spice' poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat summersweet 'Ruby Spice'?
Mostly not. NC State lists it as resistant to deer. No plant is proof against a hungry deer in a hard winter, but this one is low on the menu.
Will summersweet 'Ruby Spice' spread?
It spreads sideways, by runners or roots; the risk of it taking over is moderate. Spreads slowly by suckers into a wide clump. Remove unwanted shoots at the base.
What flowers after summersweet 'Ruby Spice'?
Summersweet 'Ruby Spice' is over by mid August. These start as it finishes and carry the same spot on, so it never goes flat:
- Japanese anemone: from mid August to early October, 3 ft tall, to stand in front of it and cover its fading stems.
- Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
- Little bluestem 'Standing Ovation': from early August to mid September, 3½ ft tall, to stand in front of it and cover its fading stems.
What does summersweet 'Ruby Spice' look like in winter?
Summersweet 'Ruby Spice' drops its leaves and stands as bare branches. That is when to see its shape, and to prune it if it needs pruning.
Is summersweet 'Ruby Spice' good for bees and butterflies?
Summersweet 'Ruby Spice' is visited by pollinators, bees, specialist bees, butterflies, hummingbirds and songbirds.
It is native to the United States and Canada (this is a named variety of the native plant).
More Clethra
- Summersweet Clethra alnifolia
- Summersweet 'Hummingbird' Clethra alnifolia 'Hummingbird'
In these guides
- Plants for deep shade
- Plants for wet soil and rain gardens
- Salt-tolerant plants for roadsides and coasts
- Plants for slopes and banks
- Deer-resistant plants for shade
- Pet-safe plants for a sunny border
- Pet-safe plants for shade
- Native plants for shade
- Garden plants native to Canada
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
- Plants that feed garden birds
- Plants with spires: vertical accents
Zone guides: Zone 4 · Zone 5 · Zone 6 · Zone 7 · Zone 8 · Zone 9
Every fact on record
- Type
- Shrub
- Size
- 6 ft (180 cm) tall, 4 ft (120 cm) wide
- Plant
- 3½ ft (100 cm) apart
- Height class
- Very tall (5 to 6½ ft)
- Place in the bed
- Back
- Flowers
- Mid July to mid August; upright spires; pink
- Leaves
- Medium texture, deciduous; dark green
- Shape
- Upright, spreading
- Hardy in
- USDA zones 4 to 9
- Light
- Full sun, part sun, part shade
- Soil
- Rich, evenly moist
- Water
- High
- Feeding
- None needed
- Family
- Clethraceae
- Comes from
- Eastern North America
- Attracts
- Pollinators, bees, specialist bees, butterflies, hummingbirds, songbirds
- Stands up to
- Deer, salt, wet soil, deep shade, erosion
Checked against NC State Extension and VASCAN (plants of Canada). Flowering times are for zone 5: later in colder zones, earlier in warmer ones. Toxicity and spread information is a general gardening guide, not veterinary or medical advice, and invasive status varies by region. If a person or pet eats a plant, contact poison control or a vet. Check your local invasive species list before planting anything with a spread warning.