Shrub · Lamiaceae
Bluebeard
Caryopteris × clandonensis
Give bluebeard a hard cut each spring and it rewards you with a soft haze of blue flowers just as the rest of the garden settles down.
Full sun
Every 7–14 days
USDA 5–9
24–35 in · 60–90 cm
Overview
Bluebeard is a small deciduous shrub loved for the cloud of blue flowers it opens in late summer, and it is a forgiving plant to start with. It sits in the mint family and keeps to a comfortable 2 to 3 feet (60 to 90 cm) tall and about the same across, so it slips easily into a border or a sunny corner without taking over. Brush past the gray-green leaves and they greet you with a clean, fresh scent.
The real charm of this shrub is when it shows up. The flowers open from July into September, long after most shrubs have called it a day, and they bring in bees and butterflies just when other nectar grows scarce. Because it blooms on new wood, you can count on it to rebuild itself each year from a hard spring trim, which makes mistakes easy to recover from.
Once it has settled in, bluebeard asks very little of you. Offer it full sun and lean, fast-draining soil and it takes heat and drought in stride. Its one true dislike is wet feet, so the surest way to lose a plant is to leave it sitting in soggy ground, and that is simple enough to avoid.
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
Give bluebeard full sun, ideally 6 or more hours each day. It will put up with a touch of partial shade, but shade is the quickest way to end up with weak, leaning stems and only a thin scatter of flowers.
Water
Once it has settled in, this is a drought-tolerant shrub that asks for very little. Water it deeply, but only when the top half of the soil has dried, which works out to about every 7 to 14 days, and never leave it standing in water, since that rots the crown and roots.
Soil
Plant it in average, loose, well-drained soil, either loamy or sandy. Rich ground actually does it more harm than good, and the one thing it cannot survive is wet feet, so good drainage matters far more than how fertile the soil is.
Temperature
Bluebeard is tough across a wide span, from about -20°F to 100°F (-29°C to 38°C). At the colder end it may die back to the ground over winter and sprout again in spring, which suits its bloom-on-new-wood habit perfectly and is nothing to fret over.
Humidity
Plain outdoor air is all it asks for, so there is nothing here for you to measure or worry about. Good airflow and dry roots matter far more to it than any moisture in the air.
Feeding
Go easy at feeding time. A single balanced feed or a little compost in spring is plenty, and overdoing it only grows soft, leaning stems that flop and bloom poorly.
Pruning
This is the one task that really counts, and it is a simple one. Cut the whole plant back hard to 6 to 12 inches (15 to 30 cm) in late winter or early spring before new growth begins, because every flower comes on the fresh wood that follows.
Repotting
Bluebeard belongs in the ground and rarely needs repotting. If you do grow one in a pot, only move it up a size when the roots circle the inside or water runs straight through.
Size & spacing
Each plant settles into a neat mound of 2 to 3 feet (60 to 90 cm) tall and roughly the same across. Leave about that much room around it so air can move freely and the rounded shape can fill in nicely.
When to plant
Bluebeard keeps a friendly, predictable yearly rhythm. Set new plants out in spring once the frost has gone, give established shrubs a hard cut before they wake from dormancy, and the blue flowers will follow 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 gives you very little trouble, and what little there is almost always comes back to soggy soil or not enough sun. Catch the early signs below and the cure is usually as simple as better drainage, more light, or a well-timed prune.
Stems wilting and darkening near the base while the soil stays damp
When the lower stems turn black and the plant folds even though the ground is wet, crown and root rot is the cause, and it takes hold when roots stay too long in soggy soil. Scratch down and you may find the roots dark and soft, with water lingering well after you stopped. Don't lose heart: lift any plant that is far gone, mix grit into the bed or shift the shrub to a higher, free draining spot, and water more sparingly from here on.
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 bloom and soft, leaning stems
If the stems grow soft and lean and the flowers barely show, it usually comes down to too little sun, a skipped spring prune, or soil that is too rich, and all three are easy to put right. Since bluebeard blooms on the new wood it makes each year, move it into full sun, cut it back hard in late winter or early spring, and hold off on feeding. Give it lean ground and a bright spot and the flowers will come back for you.
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
Here is some reassuring news for homes with animals: bluebeard is safe. The ASPCA lists it as non-toxic to pets, and there is no record of it harming livestock, birds, or people. You can plant it wherever curious noses wander.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
You can relax with a cat in the house, because a quick nibble will not poison it. The most a large mouthful of any plant might do is unsettle a cat's stomach for a day, and that soon passes.
Dogs None
There is nothing in bluebeard that will hurt a dog. If one chews a stem, the worst you might see is a bit of loose stool, and that clears up on its own.
Horses Safe
Feel free to plant bluebeard near where horses graze, since it holds nothing known to do them any harm.
Rabbits Safe
Rabbits are safe around the shrub, and they usually pass over the aromatic leaves anyway.
Livestock Safe
Cattle, goats, and sheep have nothing to fear from this shrub, and its strong scented foliage rarely draws a grazing animal in the first place.
Birds Safe
Birds come to no harm near bluebeard. The late summer flowers welcome bees and butterflies, so the shrub becomes a happy, busy corner of the garden.
People Safe
No part of the plant will poison a person. It is not grown for the table, so there is no need to taste it, but a stray leaf will do no harm at all.
No special handling required; as with any plant, ingestion of large amounts may cause mild gastrointestinal upset.
Varieties
A handful of named cultivars cover most of what you will meet at the nursery, and they differ mainly in flower shade, leaf color, and size. These are the ones worth getting to know.
Dark Knight
A tidy little mound of 2 to 3 feet that carries deep blue to bluish-purple flowers.
Longwood Blue
Taller than most at around 4 feet, with violet-blue flowers that sit prettily against silvery gray-green leaves.
Worcester Gold
Its golden-yellow leaves and light lavender-blue flowers come together in a lovely two-tone display.
Blue Mist
Its name comes from the gentle powder-blue of its flowers.
How to propagate
Bluebeard is an easy plant to multiply, and the method you choose simply depends on whether you want an exact match or are happy with a little variation.
Stem cuttingsEasy
Late spring to summer · Several weeks to root
Making more bluebeard is friendlier than you might expect, and softwood or semi-hardwood cuttings taken in late spring or summer are the simplest path. Take a healthy shoot, settle it into moist mix, and over the next several weeks it roots into a young plant just like the one it came from.
SeedModerate
Spring · Weeks to germinate
Sowing seed in spring works too, and the seedlings come up over a few weeks, but named cultivars will not come true from seed. The results vary, so if your heart is set on a certain variety, cuttings are the kinder route to take.
Myths
Cutting bluebeard back hard in spring loses you the flowers for that year.
There is no need to worry here, because bluebeard makes its flowers on the new wood it grows each season, so a hard spring cut costs you nothing. It pushes out stronger flowering stems instead, and that is why the yearly trim is the advice you will hear again and again.