Shrub · Lamiaceae
Bluebeard
Caryopteris × clandonensis
After a hard spring cut, bluebeard veils its stems in a soft haze of small blue flowers late in the season.
Full sun
Every 7–14 days
USDA 5–9
24–35 in · 60–90 cm
Overview
Bluebeard is a small deciduous shrub in the mint family, named for the cloud of blue flowers it carries in late summer. The blooms gather in soft, hazy clusters along the stems, fine and many rather than large and showy. Its narrow gray-green leaves release a clean scent when bruised, and the whole shrub holds a rounded shape at 2 to 3 feet (60 to 90 cm) tall and about as wide.
Up close, the flowers are what catch the eye. They open from July into September in misty drifts of blue, set against the muted gray-green of the foliage, and the bees and butterflies they pull in crawl over the small clustered blooms. Because each flower forms on new wood, the season's fresh stems carry the entire display.
The plant itself is lean and undemanding. Given full sun and lean, fast-draining soil, its slim stems and aromatic leaves hold up well through heat and drought. Roots left in wet ground are its undoing, the dark, soft rot at the crown being the most common way a plant is lost.
Care
The short version: full sun, lean and well-drained soil, a deep drink only when the top of the soil dries, and a hard cut back to 6 to 12 inches every late winter or early spring.
Light
Bluebeard wants full sun, ideally 6 or more hours a day. Light partial shade is tolerated, but in shade the stems grow thin and lax and the blue clusters thin out to a scatter.
Water
Once established, this is a drought-tolerant shrub. Water deeply but only when the top half of the soil has dried, roughly every 7 to 14 days, since standing water rots the crown and roots to a dark, soft mass.
Soil
Plant it in average, loose, well-drained soil, loamy or sandy. Rich ground does more harm than good, and wet feet are the one thing the roots cannot survive, so drainage outweighs fertility.
Temperature
Bluebeard is hardy from about -20°F to 100°F (-29°C to 38°C). At the colder end the top growth dies back to the ground over winter and fresh stems rise again in spring, which suits its bloom-on-new-wood habit.
Humidity
Ordinary outdoor humidity is all it needs, so there is nothing to track. Open air around the stems and dry roots matter far more than moisture in the air.
Feeding
Feed it lightly. A single balanced feed or some compost in spring is plenty, since overfeeding only pushes soft, leaning stems that flop and carry few flowers.
Pruning
Pruning is the one task that shapes the plant. Cut the whole shrub back hard to 6 to 12 inches (15 to 30 cm) in late winter or early spring before new growth starts, since every flower forms on the fresh stems that follow.
Repotting
Bluebeard is grown in the ground and rarely needs repotting. In a container, it moves up only when roots circle the pot or water runs straight through.
Size & spacing
Each plant builds a rounded mound of 2 to 3 feet (60 to 90 cm) tall and roughly as wide. About that much room around each lets air move through the stems and the rounded form fill in.
When to plant
Bluebeard moves through a simple yearly cycle. New plants go in during spring once frost has passed, established shrubs are cut back hard before the buds break, and the hazy blue flowers open from midsummer into early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: spring after last frost
- Harvest: late summer to early fall (July-September)
Hardiness
USDA hardiness zones: 5–9
Temperature: down to -29°C
Troubleshooting
Bluebeard shows few problems, and nearly all of them trace to wet soil or too little sun. The early signs in the stems and leaves below usually clear with better drainage, more light, or a well-timed prune.
Drooping growth and blackened lower stems above wet soil
Lower stems that darken to black while the leaves droop and the plant sinks are the marks of crown and root rot, which creeps in once the roots are left standing in wet ground. Scrape away the soil and the roots show dark and soft to the touch, the earth around them still wet long after a watering. Lift out the worst plants, fold sharp grit through the bed or shift the shrub to a raised, free draining spot, and let the soil dry more between drinks.
Fix:
- Remove and discard severely affected plants
- Improve drainage by amending soil with grit or replanting in a raised, well-drained site
- Reduce watering frequency
Thin, leaning stems carrying few flowers
Stems that grow thin and lean over, dotted with only a scatter of bloom, usually trace to too much shade, a skipped spring prune, or soil that is too rich. The flowers form on new wood, so full sun, a hard cut in late winter or early spring, and leaner ground bring back the dense blue clusters. Lean soil and strong light return the plant to its full, flower laden form.
Fix:
- Site in full sun (6+ hours)
- Cut back hard in late winter or early spring to force vigorous flowering new growth
- Avoid overfeeding and overly rich soil
Toxicity
For a home with animals, bluebeard is safe. The ASPCA lists it as non-toxic to pets, with no record of harm to livestock, birds, or people. The aromatic leaves and blue flowers can be planted where curious noses roam.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats are safe around bluebeard, and a nibble at the leaves will not poison them. A large mouthful of any plant can leave a cat with mild stomach upset for a day, but that is the limit of it.
Dogs None
Dogs come to no harm from bluebeard, since it holds no toxin for them. A chewed stem might bring a little loose stool, and that clears on its own.
Horses Safe
Bluebeard is safe to plant where horses graze, as it carries nothing known to harm them.
Rabbits Safe
Rabbits are safe near the shrub, and they tend to pass over the scented, gray-green leaves anyway.
Livestock Safe
Cattle, goats, and sheep face no danger from this shrub, and its strong scented leaves rarely tempt a grazing animal to it.
Birds Safe
Birds are safe near bluebeard. The blue late summer flowers draw bees and butterflies that work over the clustered blooms through the warm weeks.
People Safe
No part of the plant is poisonous to people. It is not grown to be eaten, so there is no reason to taste it, but a stray leaf does no harm.
No special handling required; as with any plant, ingestion of large amounts may cause mild gastrointestinal upset.
Varieties
A few named cultivars cover most of what the nursery carries, set apart by the color of their flowers and leaves and by their size. These are the ones worth knowing up close.
Dark Knight
A compact 2 to 3 foot mound dense with flowers in deep blue to bluish-purple.
Longwood Blue
Taller than most at about 4 feet, its violet-blue flowers standing out against silvery gray-green foliage.
Worcester Gold
Golden-yellow leaves set close beneath light lavender-blue flowers for a vivid two-tone contrast.
Blue Mist
Named for flowers of a soft, powdery blue.
How to propagate
Bluebeard is easy to multiply, and the method depends on whether you want a plant identical to the parent or do not mind variation in flower and form.
Stem cuttingsEasy
Late spring to summer · Several weeks to root
The easiest way to raise more bluebeard is from softwood or semi-hardwood cuttings taken in late spring or summer. Strip the leaves from a healthy shoot, press it into moist mix, and pale new roots form over the next several weeks, giving a plant identical to the parent.
SeedModerate
Spring · Weeks to germinate
Seed sown in spring sprouts over a few weeks, but named cultivars will not come true from it. The seedlings vary in flower color and form, so cuttings remain the route to a particular variety.
Myths
A hard spring pruning strips bluebeard of the year's flowers.
The cut takes nothing away, because bluebeard forms its flowers on the new wood it grows each season. A hard spring cut drives stronger, more flower laden stems, which is why the yearly cut is the standard advice.