Santolina

( san - toh - LEE - nuh )

At-A-Glance Information

This genus of evergreen shrubs, commonly called Cotton Lavender, Holy Flax or Lavender Cotton, includes species which need full sun and little to moderate water to perform well in the landscape. They are native to the Mediterranean region (southern Europe, the Caucasus, and northwestern Africa) and have fragrant green to silvery foliage. Profuse blooms of yellow flowers increase interest in summertime. These plants are great as groundcovers, informal edgings, bank covers, or low sheared hedges. They are commonly grown in container, pollinator, drought-tolerant and xeric landscapes. Take care when planting these shrubs in the garden, as plant parts produce strong, aromatic oils that can irritate skin if touched or cause stomach upset in pets if ingested.

Santolina Species and Varietals

The genus Santolina includes about 20 species, and is a member of the Daisy family (Asteraceae). The plants in this genus are closely related to those in Chamaemelum (Chamomile), Artemisia (Wormwood), Achillea (Yarrow), and Tanacetum (Tansy). The best growing zones for Santolina vary depending on the species. For more information, see the descriptions below. To find your zone, click here: Zone Map.

Santolina chamaecyparissus (Santolina incana) (Lavender Cotton, Cotton Lavender, Gray Santolina)
This species of Santolina grows well in USDA hardiness zones 6-9 or Sunset growing zones 2-24, H1 and H2, and reaches 2 feet tall and 3 feet wide at maturity. Stems are woody and brittle and leaves are rough and white-grey. Cultivars include 'Nana' (to 1 foot tall and 2-3 feet wide), 'Pretty Carol' (16 inches tall and just as wide) and 'Lemon Queen' (to 2 feet tall and wide, with creamy-yellow flowers).

Santolina pinnata (Santolina ericoides) (Lavender Cotton, Apuan Mountain Lavender-Cotton, Rosemary-Leaved Lavender Cotton)
This species does well in USDA hardiness zones 6-9 or Sunset growing zones 3-24 and reaches 2-2.5 feet tall and 3 feet wide with dark green narrow leaves and cream-colored flowers. Variety Santolina pinnata neapolitana reaches 12-15 inches tall with silvery foliage and bright yellow flowers and is commonly called 'Rosemary-Leaved Lavender Cotton', due to the foliage resemblance to Rosemary shrubs.

Santolina rosmarinifolia (Santolina virens) (Holy Flax, Green Lavender Cotton, Green Santolina)
Best in USDA hardiness zones 6-9 or Sunset growing zones 3-9 and 14-24, this species reaches 2 feet tall and 3 feet wide, with green leaves resembling those of Rosemary plants. Flowers are bright yellow and bloom in summertime. Cultivars include 'Morning Mist' (compact with silvery foliage and good in heavy soils), and 'Lemon Fizz' (with chartreuse to golden foliage).

Caring for santolina

Take care when planting these shrubs in the garden, as plant parts produce strong, aromatic oils that can irritate skin if touched or cause stomach upset in pets if ingested. Plant Santolina 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 and overall performance. When they are grown in less light, they will not flower as profusely and stems have a tendency to become etiolated. Space these plants 18 to 24 inches apart for a groundcover or natural mounding effect, or 12-15 inches apart for a tight, continuous hedge. Ensure that soil is well-draining, rich in nutrients, and has a pH of between 6.8 and 8.2 (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, sand and perlite before installing. 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 very drought-tolerant, able to get by on rainwater alone for much of the year with supplemental irrigation during extended periods of dry weather.

Santolina shrubs do not need to be fertilized, they grow well in poor, rocky soils and adding too much additional organic matter or nutrient load to the soil can cause plants to become weak and floppy and lose their strong scent. Pruning is simple; remove any damaged, diseased, or dead foliage at any time during the growing season, and remove spent flowers to neaten up the appearance of plants and encourage reblooms. Each winter or early spring, cut the entire plant back by 40% to 50%, making sure to never cut into bare old wood, which will not regenerate. Plants are typically pulled and replaced when they become woody and bare in the center, a tendency which can be delayed through these yearly rejuvenation prunings. In cooler regions, plants will die back to the ground annually and re-sprout in springtime. Santolina plants can be expected to survive in the landscape for between 3 and 10 years depending on growing conditions.

Caring for Santolina in Containers
Santolina shrubs do very well in the ground, but can also be grown in containers with proper care. Growing these shrubs in containers can allow for gardeners in cooler zones to cultivate these fragrant plants; they can simply be brought into a sheltered location over the winter months. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. When these plants are mature, they require at least a 10-14 inch wide pot with very large drainage holes. Fill with a well-draining potting mix amended with organic material, sand and perlite, and top with a layer of organic or rock mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Santolina plants grown in containers are still considered very drought tolerant, but they will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

Santolina 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 Santolina 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 spring or early summertime, 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, 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 Santolina 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 paper bag, 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. The seeds are held in spherical, dried flower heads that will turn brown and become brittle.
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 to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area 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 7-14 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.

Propagating Santolina by Division
This type of propagation is relatively simple; you will need a clean shovel, mulch, fresh soil (any kind will do, though it does need to be well-draining), compost, gloves and other protective wear (to prevent skin contact) and pots (only necessary if you will be saving divided plants for transporting elsewhere). Division is best done in spring or fall and needs to be done every four to five years for best results. To propagate by division, follow these steps:

Dawn your protective gear and gather your materials. Using a shovel, dig up your existing plant. Start from the outside and work your way in to avoid damaging the root system. Once you have worked it up out of the ground, lay it out.
Start to tease apart the roots with your fingers, rinsing off dirt if necessary. Once the roots are untangled, separate your plant into segments, ensuring that each is free from rot and disease. Put any diseased plant parts in the garbage, not the compost bin.
Prepare your pot(s) or new planting site(s) with amended, well-draining soil. You can either bring in new soil or simply amend your existing soil with compost to complete this task. Then, plant your divided plants and water thoroughly.
Apply a thick layer of mulch over the new planting to protect it from cold weather as it acclimates to its new home. Then, enjoy watching it sprout.