Deinanthe caerulea
Blue deinanthe, False hydrangea
Also known as Hydrangea caerulea
- Height × spread
- 0.46m × 0.5m
- Position
- Part shade
- Hardiness
- Cold to -15C (RHS H5)
- Flowers
- Summer
Availability
Please ask in store about availability
Many plants are seasonal. Call 01234 567890 to check current stock.
About this plant
This is a shade loving foliage plant that is grown for its beautiful large leaves and for the lovely but short lived flowers. The leaves are rounded in appearance and are held in pairs. They're characterful with deep veins, somewhat bristly hairs and toothy edges. The flowers, coming in summer, during July and August, may be likened in some ways to a begonia. They are a curious slatey blue colour and have blue stamens. They are held on reddish stems. They need cool positions where there is always plenty of moisture, a rich soil, and a part or lightly shaded position. They are easily damaged in windy sites so give them shelter and avoid frost pockets. The happier the plant, the more luxuriant and impressive the foliage.
- Flower colour
- Blue
- Foliage colour
- Green
- Stem colour
- Red
- Variegated
- No
- Scent
- No
- Shape
- Dome
- Height
- 0.46m
- Spread
- 0.5m
- Season of interest
- Summer
- Flowers in
- Summer
- Evergreen
- Deciduous
- Garden style
- Shady court
- 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
- Hardiness
- Cold to -15C (RHS H5)
- Borders & containers
- Borders
- Use for
- Wall cover
- Walls
- North, East facing
- 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.
Spring - early-mid · Planting
Divide when too large
The plant can be divided if it becomes too large or another plant is required. This may involve physically dividing the clump in two, removing offsets or small bulbs or dividing rhizomes. The new plants can be grown in pots or planted in the ground.
Planting & general
Outdoors
Water with rain water
This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.
Compost · Planting
Ericaceous compost
This plant requires acidic (ericaceous) soil. Where the soil is not acidic, or when planting in pots, use an ericaceous compost.