When you discover lavender cotton for your flower garden, you’ll categorize it as one of those plants you wish you had known about when you first started gardening. Why don’t the big box stores feature hardy specimens like these instead of the ubiquitous marigolds and daylilies? At home in the xeriscape or seaside garden, in containers or the herb garden, lavender cotton is lovely in or out of bloom.
Santolina chamaecyparissus goes by several common names, including gray santolina, ground cypress, holy herb, lavender cotton, and petite cypress.
Lavender cotton is generally hardy in zones 6 to 9. Plants in raised beds with sharply draining soil may be hardy to zone 5. Plants that sit in mushy dense soil throughout winter thaws and freezes are less likely to perennialize.
With proper care, your plants should attain a height of one to three feet, spreading about three feet across. Lavender cotton needs a full day of sun to maintain its compact shape. In the shade, the plants will become leggy as they strain towards the light.
Lavender cotton plants have such amazing foliage that in full sun it appears gleaming silver, on cloudy days it’s a cool seafoam hue, and at dusk, it takes on almost a bluish cast. The bright yellow one-inch flowers are held erect on wiry green stems. Lavender cotton blooms from early to mid-summer. Deadheading will not prolong blooming or cause repeat blooming, but will maintain a tidier plant.
Pick a site with good drainage for your lavender cotton plants, but don’t over-amend the soil with rich organic matter. Organic amendments like compost and humus acidify the soil, and lavender cotton prefers a slightly alkaline soil. Areas with low rainfall tend to have alkaline soil but test the soil pH if you aren't sure. If your soil is acidic, you may add ground limestone or wood ashes to bring the soil to an alkaline pH up to 8.5, keeping in mind the tolerance of its companion plants.
In areas with heavy soils, plant lavender cotton in raised beds or containers. You can amend the soil with grit, gravel, or sand to increase drainage and keep fungal diseases at bay.
Although lavender cotton is a drought-tolerant plant, an inch of water per week during the first growing season will help the plant develop a strong root system. After the blooms fade, you can cut the plant back by half to keep a pleasing rounded form. When several hard freezes have occurred, you can shear the plant back to the soil level. Don’t wait until spring to do this, or you may sacrifice the blooms.
Additional fertilizer isn’t necessary for lavender cotton plants, which prefer the poor and rocky soils similar to their native Mediterranean region. Insects aren’t a problem; in fact, sachets of lavender cotton act as natural insect and moth repellants.
If lavender cotton isn’t reliably hardy in your area, or if you want to make more plants, propagate by making stem cuttings in the spring. If your plant gets large and unwieldy, take advantage of the flopping stems by layering, which simply means burying the stem end closest to the plant until it forms new roots. Then you can snip off the new plant at the end of the season and place it in your garden.
Lavender cotton will thrive in your rock garden, where the absorbed heat of the rocks will offer extra winter protection. The dependable neat form of lavender cotton also makes it attractive in knot gardens.
Pair lavender cotton with drought-tolerant plants that have contrasting red or burgundy foliage, such as ‘Purple Emperor’ sedum or ‘Husker Red’ penstemon. Place lavender cotton at the edge of a well-traveled border, where you can enjoy the aromatic foliage as you brush by. Deer and rabbits are deterred by the same fragrance we take pleasure in, and will rarely browse these plants. However, butterflies and bees will flock to the yellow pompon blossoms when they appear.
If you're intrigued by the trend of green roofs, lavender cotton is an ideal specimen for this architectural modification. Although a roof that hosts growing media and vegetation usually requires the assistance of a professional, a DIY green roof is attainable for a shed or chicken coop. Adding a green roof planted with lavender cotton can benefit your landscape by extending the available gardening footprint available to you, and by attracting more beneficial pollinators to your garden.