Groundcover Herbs

Don’t overlook groundcover herbs for plant health and fragrance.

Do groundcover herbs have a role to play in the food garden? The answer is yes to the power of three (or more)! They are pest repellents, attract pollinators with their flowers and transform ordinary pathways into an aromatic delight, as the leaves release their fragrance underfoot.

The four groundcover herbs we’re talking about are thyme (there are four groundcover varieties), creeping oregano, lawn chamomile and lawn pennyroyal. But they are not just for pathways: these herbs can also be used as pest-repelling groundcovers grown under or between veggies like tomatoes, brinjals and peppers. In gardens where crops are set out in rows, herb groundcovers planted between the rows attract bees and get plenty of sun, which allows them to thrive.

Use companion-planting principles when deciding how to mix and match groundcover herbs with veggies. According to the Margaret Roberts guide to companion planting, oregano and thyme are good companions with brinjals, cucumber, peppers, pumpkins, tomatoes and squashes. At her herb centre, pennyroyal was planted under tomato vines, peppers and strawberries, while chamomile kept aphids away from the brassicas and also improved their flavour.

Groundcovers that form a mat, like pennyroyal and chamomile, are also an effective green mulch, keeping the soil cool and moist. Pennyroyal is a good ant repellent while lawn chamomile acts as a plant doctor to surrounding plants. When planted along the edge of the bed, groundcover herbs help to suppress weeds, which always seem to colonise the bed edges before making inroads into the beds.

Thyme varieties for pathways

Groundcover thymes are spreading ground huggers that produce a dense mat of leaves. Although they tolerate a fair amount of foot traffic, consider using stepping-stones so that the thyme doesn’t bear the full brunt of the feet. All thymes need full sun and light soil that drains well.

Bressingham thyme (Thymus doerfleri) is a spreading 2cm high variety, free flowering with pink/purple flowers and tiny, aromatic grey-green hairy leaves that form a dense mat.

Creeping thyme (Thymus coccineus) also has very small, fine aromatic leaves that form a carpet. It has a slightly higher growth (up to 7cm) and has crimson-pink flowers in summer. Clipping maintains the dense texture.

‘Doone Valley Thyme’ (hybrid) has lemon-scented leaves with heads of small purple flowers. It grows 5cm high but has the more open growth habit of a spreading groundcover.

White thyme (Thymus serpyllum ‘Alba’) has tiny, bright green leaves and white flowers. It is a very good groundcover, and although it can grow up to 30cm, it responds well to clipping and then develops a mat-like texture.

A lure for ladybirds

Lawn chamomile (Anthemis nobilis) has a fresh apple-like scent and tiny white daisy flowers that attract ladybirds, lacewing, hoverfly and wasps. Plants spread 40cm and the flowers rise up to 30cm in height. Lawn chamomile doesn’t tolerate heavy foot traffic, making it more useful as a low groundcover or as a bed edging. Grow it near ailing plants to revive them. It is a frost-hardy, evergreen perennial that is not invasive. Plant lawn chamomile in full sun or semi-shade in fertile, well-composted soil that drains well. Water regularly. Harvest the flowers to make a soothing, stress-relieving tea.

Powerful peppermint

Although pennyroyal (Mentha pulegium) is known for repelling ants with the pungent peppermint aroma of its leaves, it also attracts beneficial insects like hoverfly and wasps with its clusters of soft purple flowers in spring, making it a good companion plant for broccoli, Brussels sprouts, cabbage, cauliflowers, squashes and tomatoes. Plant in areas that receive full sun to partial shade and enrich the soil with plenty of compost for good drainage and nutrition. Trim regularly to encourage mat-like growth and to control its spread. Don’t grow it near parsley and do not use the leaves for tea or medicinally as they can be toxic in very large doses.

Pretty and practical

The two creeping oregano varieties are so pretty that this is a good enough reason to plant them. Golden oregano (O. vulgare ‘Aureum’), true to its name, has beautiful yellow leaves, with a mild taste that makes it suitable for a wide range of dishes. Oregano ‘Country Cream’ has oval, variegated cream-and-green aromatic leaves with tiny clusters of small pink flowers in summer. The leaves have a stronger flavour that works well with meat and vegetables.

Both have a garden height of 10cm and spread of 12cm. Plant in full sun in well-drained composted soil. As companion plants they can be planted with broccoli, cabbage, cauliflower, cucumber or peppers. Or better still, use them for contrast planting, as edgings or border plants or between other herbs.