Galium odoratum
Galium odoratum, also known as Sweet Woodruff, is a low-growing evergreen herbaceous perennial native to southern Europe and western Asia. It is a lemon-scented, shade-loving woodland ground cover that thrives in dappled shade or light morning sun. This carpet of small, narrow, bright green foliage remains green in winter and looks superb when cascading over stone walls. In late spring, dainty white four-petalled flowers appear, followed by green berries in midsummer. The sweet scent of dried leaves is strong enough to fill an entire room.
Galium odoratum prefers moist well-drained soil, but it is tolerant of drier soil conditions. In spring and summer, water this hardy ground cover deeply but infrequently, allowing the soil to dry out somewhat between waterings. During the heat of summer, it may benefit from more frequent, light waterings to keep the foliage looking lush. In winter, reduce water and keep it on the dryer side to reduce the risk of rot.
Galium odoratum grows best in partial to full shade. In the wild, it grows around trees for protection. When grown in too much sun, the foliage tends to get yellow and crispy. Too much shade will make foliage lax and lead to minimal flower production. If you want to have beautiful blooms, it is best to plant this hardy ground cover in dappled shade or lightly filtered morning sun.
Galium odoratum is hardy in USDA hardiness zones 4-8, and is tolerant of both cold and heat. The preferred temperature range for growth is 55 to 75 Fahrenheit during the day and 40-50 Fahrenheit at night. Avoid frost as this can damage the foliage and slow down growth.
This shade-loving ground cover prefers a humid environment, as it is native to tropical climates. Too much humidity can lead to disease and can even cause the growth of fungal leaflets. It also prefers more air circulation in humid climates so it is best to provide some air movement around your plant in humid areas.
Galium odoratum prefers a soil that is loose, well-draining, and rich in organic matter. A potting mix with peat moss, perlite, and compost is recommended. For those growing Sweet Woodruff outdoors, it’s important to prepare your soil before planting or transplanting. Work in some aged compost into the soil to help it retain moisture and provide nutrients. Organic mulch can also be added to help protect the roots from temperature changes.
Galium odoratum prefers a light feed throughout the growing season, but in containers, it may need more frequent fertilizer applications. A balanced liquid fertilizer at half strength is recommended for regular fertilization. Make sure not to fertilize in the winter as the plant is semi-dormant. Instead, wait until late spring or summer when the plant begins to actively grow.
Though Galium odoratum is generally considered to be relatively pest and disease free, there are some pests that may infect the plant if left unchecked. These might include aphids, spider mites, slugs, and snails, which can affect the health and appearance of the foliage. If noticed early, these pests can be easily managed with a good horticultural soapy spray. Additionally, volcanic ash can sometimes be used to deter snails and slugs from the plant. If the infestation is severe, insecticides or fungicides can be used to control the pests.
Galium odoratum prefers a spot in a container that has well-draining soil, so it’s best to repot every two or three years. It’s important to choose a clean pot with drainage holes to ensure that excess water can escape easily. To help drainage, place a layer of stones or broken pot shards at the bottom of the pot. When repotting, it’s a good idea to add fresh soil and a light fertilizer to the soil to help it remain healthy.
Galium odoratum is a low growing ground cover, but it might need occasional pruning to keep it looking neat and tidy. This can be done anytime from late winter to early spring before the new growth begins. It’s best to prune away any yellowing or brown foliage and any branches that are displaying signs of disease or damage, as well as those that are pruning out of bounds.
Mulching Galium odoratum can help protect its roots from changes in temperature. Using a layer of organic mulch such as shredded bark or compost can also help to retain moisture in the soil and provide nutrients. If you’re growing your plant in a pot, ensuring that the potting mix is kept moist is crucial in preventing dry roots.
Galium odoratum can be propagated from both seed and division. For seed propagation, collect seeds from the flowerheads when they have fully ripened and plant them in seed trays. Keep the trays in a warm location and water regularly. For division, use a sharp spade to divide the clumps, replanting the divisions in separate pots. Water well and keep in a bright, airy location.
Galium odoratum can benefit from being staked for support. This can help keep its shape and encourage new growth. When staking, use a soft material such as jute string, twine, or cotton thread in order to avoid damaging the delicate foliage, and tie it around the stem, not the foliage.
Galium odoratum does not experience a true dormancy period, but it may become less active in the winter months. During this time, reduce the amount of water given to the plant and keep it on the dryer side. Abstain from high-nitrogen fertilizers during the winter months, and resume regular fertilization during the warm months.
After coming into contact with Galium odoratum, some humans may experience skin irritation. The same goes for pets who come in contact with the plant material. The foliage, stems, and berries are all considered toxic to both humans and animals, and ingestion is not recommended.