Caryopteris

( kare - ee - OP - ter - iss )

At-A-Glance Information

Commonly referred to as Bluebeard, this group of flowering shrubs is deciduous and require full sun. They need moderate water with good drainage and are usually grown as woody-based perennials. These shrubs are some of the few that produce truly blue flowers. Blooms are present in summer and fall on current season's growth, so they can be cut back to the ground before new spring growth occurs each year. These flowers will attract butterflies and bees to your garden, and the foliage (when crushed) smells a bit like Eucalyptus.

Caryopteris Species and Varietals

The genus Caryopteris is included in the family Lamiaceae, and there are seven species currently recognized. Caryopteris growing zones vary depending on the species; refer to the descriptions below for more growing information. To find your zone, click here: Zone Map.

Caryopteris x clandonensis (Blue Mist)
This shrub grows best in USDA hardiness zones 5-9 or Sunset zones 2b-9 land 14-24. Forms a low-growing mound 2-3 feet tall and wide. Small blue flower clusters appear at the ends of stems. Varieties include 'Petit Bleu', 'Blue Balloon' (rounded shape and lavender-scented leaves), 'Dark Knight', 'Longwood Blue' (with silvery foliage), and 'Summer Sorbet' (with yellow-edged green leaves).

Carypoteris spp. Hybrids (Hybrid Bluebeard)
This group of hybrids was created by crossing various species of Bluebeard. These cultivars are great garden ornamentals, and produce variously-shaded purple flowers.

'Arthur Simmonds'

'Blue Mist'

'First Choice'

'Heavenly Blue'

'Hint of Gold'

'Pershore'

'Sterling Silver'

'Worcester Gold'

Caryopteris incana (Common Bluebeard, Blue Spiraea, Blue Mist Spirea)
This species grows best in USDA hardiness zones 5-9 and Sunset growing zones 4-9 and 14-24. Individual plants grow to be 3-4 feet tall and 5 feet wide at maturity. Lavender-blue flowers appear at leaf joints. Variety 'Jason' (also known as 'Sunshine Blue', pictured) has golden yellow leaves and medium blue flowers.

Caring for Caryopteris

Plant Caryopteris in a space in the landscape that receives full sun; ideally, they appreciate between 6 and 8 hours of sun each day for the best blooms. When these flowers are grown in less light, they will not flower as profusely. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 6.5 and 7.5 (slightly acidic to neutral). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Caryopteris plants can quickly develop root rot and other fungal problems if soil drainage is inadequate. Apply a layer of mulch around the planting area to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water new plantings regularly as they establish a strong root system in their new home. At maturity, these plants are considered to be fairly drought-tolerant, able to get by on rainwater alone for most of the year with supplemental waterings during extended periods of drought.

Fertilize yearly in early springtime with an application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flower spikes to neaten up the appearance of plants and encourage reblooms. Caryopteris shrubs should be cut back to the ground once a year before new spring growth occurs. These shrubs bloom on new wood, so cutting it back in this manner annually ensures colorful shows of blooms. Caryopteris plants typically survive for 3-5 years in the garden before needing to be replaced. They will freely re-seed, however, providing volunteer seedlings indefinitely.

Propagation

Caryopteris can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your shrub, follow the instructions below:

Propagating Caryopteris by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In late spring, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 6 inch portion(s) of the end of a non-blooming branch and strip the leaves off of the lower half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about four to six weeks have passed, your cutting should be rooted. When you notice new growth on your propagated plant, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Caryopteris by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a plastic bag, damp sphagnum moss, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds in late fall. Once the seed pods on the shrub have dried out and begun to split open, you can harvest the seeds inside. Cut them off of the plant, placing them in a paper bag. Harvest as many as you can, and place them in the plastic bag with some damp sphagnum moss. Place your bag in a refrigerator for three months.
In late winter, water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area (about 68 degrees Fahrenheit) that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 14-21 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.