Caryopteris is a genus of blue-flowering, deciduous shrubs that is native to eastern Asia, but one species is generally grown in gardens. Known as blue mist shrub, C.x clandonensis, is a plant with brilliant blue flowers. This hybrid is not native to any area.
Several varieties of Caryopteris grew in ornamental gardens but in the early 1930s, an accidental cross-pollination occurred in England that created the species that became known as “blue mist”.
This hybrid, C. x clandonensis with clear blue flowers, won Royal Horticultural Society medals in the 1930s.
|Scientific name||Caryopteris x clandonensis|
|Common names||Blue mist, blue beard, dark spirea|
|Height||Up to 13 feet (3.96 m)|
|Width||2 feet (0.61 meters)|
|USDA Plant Hardiness Zone||Zones 5 to 9|
|Native to||Hybrid plant, not native to any area, genus native to East Asia.|
|Blooming season||Late summer|
|Plant specific features||Brilliant blue flowers, deciduous, perennial|
How to Plant and Grow a Caryopteris Bush
Normally, these plants grow from nursery container stock. You will find that blue mist is easy to care for and does not cause many problems.
When planting, prepare the planting hole with compost and if necessary a soil conditioner to improve the drainage. The crown of the plant should be level with the surface of the surrounding soil or even raised slightly. This will ensure that the water can drain away from around the base of the plant.
Where to Plant
Blue mist or blue beard is a compact plant, with silver-gray foliage. This is one of the reasons that they are a good choice in a garden environment.
You have a choice as to a planting spot – it will be equally happy in a shrubbery, a mixed herbaceous border, or if included in a small hedge planting scheme.
It flowers late in the year, which makes it particularly attractive, as not many other shrubs be blooming at this time.
When to Plant
Ideally, plant this shrub in the spring or fall. If it gets particularly cold in your region, then spring is the preferred planting time.
Don’t be concerned if the plant stays looking dead when other plants are sprouting well. The blue mist shrub takes a long tie to produce new shoots in the spring, so this is normal.
Caryopteris Shrubs Care and Maintenance
Caryopteris x clandonensis grows best in moist but well-drained growing neutral medium.
This is a plant that will tolerate drought conditions but does best if provided with adequate moisture. A young plant needs time to establish a robust root system and therefore needs regular watering until it is mature.
Once it is settled, it is a drought-tolerant plant and doesn’t normally need watering.
If you apply a light mulch or mix some organic matter into the soil at planting, that should be sufficient. There is a danger that over-fertilizing this plant will result in too much foliage at the expense of flowers.
For the best flowering display, plant in full sun. The more that the plant’s access to sunlight is restricted, the later the plant will flower and fewer flowers will be produced.
Pruning and Repotting
You can shape a blue beard to keep it neat and flowering. In early spring, you can cut it down to at least half its existing height.
You can be even more drastic if desired and cut it back to just 12 inches (0.3 m) from ground level. There will also be some dead wood to cut out each year. This can be done at any time.
In cooler regions, the plant may die back to the ground each winter. If this occurs, the dead stems need to be removed as the new growth starts to appear.
Blue spirea can and does successfully self-seed. It isn’t a plant that is designated as invasive, but its seeds are spread by flowing water, birds, insects, and animals.
If you collect the seeds, you can easily propagate blue mist shrubs and transplant the seedlings as and when you wish.
Alternatively, in the spring, you can take cuttings from the current season’s growth. The cuttings should be several inches in length. If you use hormone rooting powder, this will speed up the rooting process but is not essential.
In order to conserve moisture, remove the lower leaves of the stem cutting. Keep them out of direct sunlight but in a well-lit position.
Ensure that they are kept well watered until roots have formed. Once rooted, the seedlings can be planted out into their final positions.
Pests and diseases
There is really only one serious problem that can affect this plant. If the blue mist shrub is left sitting in water-logged soil, the roots can rot. This is known as crown rot, and the plant will die.
Of far less concern is the leaf plant bug, which can spoil the look of the foliage in early summer. Any damage caused by this insect is only cosmetic and can be eradicated with the use of horticultural oil or insecticidal soap.
Temperature and Humidity
Blue mist doesn’t need any winter protection. It is hardy to USDA zones 5, although if it is grown in a cooler region it is likely to die back to ground level in the winter.
Fortunately, this perennial shrub grows quickly and because it blooms on new wood, it isn’t damaged.
It is a good idea to remove any diseased or decaying stems from the base of the plant to prevent insect larvae from overwintering in the soil and also fungal disease.
Other Uses for Blue mist shrub
This plant is equally useful as a deciduous shrub or as a woody perennial that will die back to ground level every winter depending upon your temperature. Its later flowering period and attractive, silver-gray foliage makes this an attractive choice for the garden.
Types of Caryopteris x clandonensis You Can Grow
As well as the blue beard or blue mist hybrid Caryopteris x clandonensis, there are several other species available that are known by the same common name. However, none are as popular nor as hardy as the main hybrid.
With clouds of brilliant blue flower heads in late summer, when most other shrubs have finished blooming, this is a super addition to a garden planting scheme. Moreover, the flowers are very fragrant and will attract beneficial insects.
*image by RukiMedia/depositphotos