Rose of Sharon 'Diana'
Hibiscus syriacus 'Diana' · Malvaceae
Very large, pure white, single flowers with crinkled petals, which stay open into the evening, on a dense, upright shrub.
- Size
- 8 ft tall, 6 ft wide
- Zones
- 5 to 9
- Light
- Full sun
- Flowers
- Mid July to mid September
- Pets
- No toxicity recorded
- Job in a bed
- Anchor
A bed built around rose of Sharon 'Diana'
The planner designed this bed around rose of Sharon 'Diana' when this page was made: a 16 × 8 ft (4.9 × 2.4 m) English border in zone 6, full sun. It chose the other plants from the 966 that suit those conditions, and says below why rose of Sharon 'Diana' stands where it does.
The plants
- 1 Rose of Sharon 'Diana' × 1, white
- 2 Creeping phlox 'Emerald Blue' × 6, blue
- 3 Cheddar pinks 'Firewitch' × 35, pink
- 4 Sweet coneflower 'Henry Eilers' × 4, yellow
- 5 False sunflower 'Summer Sun' × 3, yellow
- 6 Coneflower 'Green Jewel' × 3, green
- 7 Star of Persia × 5, purple
- 8 Hardy gladiolus × 5, pink
- 9 Easter lily × 5, white
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.
Why here
- Anchors a back corner. At 8 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 sweet coneflower 'Henry Eilers' (4½ 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 11 weeks. From mid July to mid September.
- Part of the bed's peak. With false sunflower 'Summer Sun', coneflower 'Green Jewel' and Easter lily in mid July: 4 kinds at once. No week has more.
Planned as an English border: 6 of the 6 groups (100%) are drifts, longer along the bed than they are deep. Cheddar pinks 'Firewitch' is planted in 9 places along the bed, which gives it rhythm. The scheme leans cool (blue, pink and purple) and uses yellow for warmth, with white and green to calm things between them.
The planner's own design check: 9 Excellent, 7 Good, 1 Needs revision. Its weakest point is height and scale: Heights average about 12 in at the front, 2 ft in the middle and 4½ ft at the back. Along the back row the heights step up and down, between 3½ ft and 8 ft, and no two neighbours are the same height.
Open this bed in the planner Change its size, the sun or the style, move plants about, or swap one for another.
Where rose of Sharon 'Diana' goes in a border
At 8 ft it belongs at the back of a bed. In the planner's ten height classes it is super tall (over 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.
A sterile triploid from the US National Arboretum: no seedlings, and so more flowers over a longer season. The best white.
- White for late summer
- Evening gardens
- Hedges and screens
What to plant with rose of Sharon 'Diana'
Plants recorded as good partners for it, and what each pairing does:
- Garden phlox: in flower together for eight weeks, from mid July; low enough (3½ ft) to stand in front of it.
- Daylily: in flower together for five weeks, from mid July; low enough (2½ ft) to stand in front of it.
- Switchgrass 'Northwind': in flower together for seven weeks, from early August.
Questions about rose of Sharon 'Diana'
Does rose of Sharon 'Diana' need sun or shade?
Rose of Sharon 'Diana' grows in full sun (6 or more hours of direct sun a day).
It wants ordinary well-drained soil, of average fertility, and a good soak in dry spells. It copes with soil that stays wet.
What zones does rose of Sharon 'Diana' grow in?
USDA zones 5 to 9. It is hardy to zone 5, which means it survives winter nights down to about −10 °F (−23 °C).
Gardening in Canada? Use the USDA zone for your town: Canada's own zone map uses different numbers.
When does rose of Sharon 'Diana' flower in my zone?
In zone 5 it flowers mid July to mid September. As a summer flower it moves about half a week for every zone: earlier where it is warmer.
| Zone 5 | Mid July to mid September |
|---|---|
| Zone 6 | Mid July to mid September |
| Zone 7 | Early July to mid September |
| Zone 8 | Early July to mid September |
| Zone 9 | Late June to mid September |
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 rose of Sharon 'Diana' be planted?
5 ft (150 cm) apart, from the middle of one plant to the middle of the next. That is a little closer than its full width of 6 ft (180 cm), so a group knits into one patch.
It grows 8 ft (250 cm) tall. Give it the full distance from anything taller, or it will lean out towards the light.
How many rose of Sharon 'Diana' plants do I need?
Usually one. At 5 ft (150 cm) across, it is a plant you place, not one you mass. For a hedge or screen, set them 5 ft apart: three plants for a 10 ft run.
In the bed above, the planner used one in one group.
Is rose of Sharon 'Diana' poisonous to dogs and cats?
No toxicity is recorded for dogs, cats, horses or people, according to NC State Extension and the ASPCA.
"Not toxic" is not "edible": a pet that eats a lot of any plant can be sick.
Do deer eat rose of Sharon 'Diana'?
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.
What flowers after rose of Sharon 'Diana'?
Rose of Sharon 'Diana' is over by mid September. These start as it finishes and carry the same spot on, so it never goes flat:
- Garden chrysanthemum: from mid September to late October, 24 in tall, to stand in front of it and cover its fading stems.
- Swamp sunflower: from late September to late October, 6½ ft tall.
- Montauk daisy: from mid September to late October, 3 ft tall, to stand in front of it and cover its fading stems.
What does rose of Sharon 'Diana' look like in winter?
Rose of Sharon 'Diana' drops its leaves and stands as bare branches. That is when to see its shape, and to prune it if it needs pruning.
Is rose of Sharon 'Diana' good for bees and butterflies?
Rose of Sharon 'Diana' is visited by pollinators, specialist bees, butterflies and hummingbirds.
More Hibiscus
- Hardy hibiscus Hibiscus moscheutos
- Hardy hibiscus 'Kopper King' Hibiscus 'Kopper King'
- Hardy hibiscus 'Lord Baltimore' Hibiscus 'Lord Baltimore'
- Rose of Sharon Hibiscus syriacus
- Rose of Sharon 'Blue Chiffon' Hibiscus syriacus 'Notwoodthree' (Blue Chiffon)
- Rose of Sharon 'Sugar Tip' Hibiscus syriacus 'America Irene Scott' (Sugar Tip)
- Scarlet rose mallow Hibiscus coccineus
In these guides
- Plants for wet soil and rain gardens
- Salt-tolerant plants for roadsides and coasts
- Pet-safe plants for a sunny border
- Plants for hummingbirds
- Plants for butterflies
- Plants for bees
- Plants for a white garden
Every fact on record
- Type
- Shrub
- Size
- 8 ft (250 cm) tall, 6 ft (180 cm) wide
- Plant
- 5 ft (150 cm) apart
- Height class
- Super tall (over 6½ ft)
- Place in the bed
- Back
- Flowers
- Mid July to mid September; open bowls; white
- Leaves
- Medium texture, deciduous; dark green
- Shape
- Vase-shaped, clumping
- Hardy in
- USDA zones 5 to 9
- Light
- Full sun
- Soil
- Average, well-drained
- Water
- Moderate
- Feeding
- Light, in spring
- Family
- Malvaceae
- Comes from
- S. China, Taiwan
- Attracts
- Pollinators, specialist bees, butterflies, hummingbirds
- Stands up to
- Deer, heat, salt, wet soil
Checked against NC State Extension and ASPCA poison lists. 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.