Rock cress is one of the best-kept secrets of spring. A low-level, groundcover plant, it grows quietly in the garden, easily overlooked for most of the year. Then in early spring, it suddenly bursts into bloom and makes you sit up and take notice. Rock cress is the common name for several different plants, all of them species of either Arabis or Aubrieta. Part of the Brassica family, they’re the better-looking cousins of cabbage, Brussels sprouts and broccoli. But despite their dainty appearance, rock cresses have the ability to settle in the toughest of spots, growing happily in the cracks of a wall or on slopes with poor soil where nothing else will flourish. And luckily for us gardeners, there are plenty of easy-to-grow varieties.
How to grow Arabis
The most popular varieties of Arabis are the mountain rock cresses, Arabis alpina subsp. caucasica. That ‘alpina’ in their name is a clue to their preferred growing conditions - found naturally on high rocky slopes, with poor soil, they’re ideal for rock and gravel gardens. They do best in sunny spots with very well-drained soil, so if your soil is heavy, add lots of horticultural grit to it before planting to improve the drainage. They’ll flower all spring, smothered in masses of tiny pink, white or mauve blooms. Once they’re finished, shear them over to keep them looking tidy. Excellent low-maintenance groundcover plants, they look lovely planted with spring bulbs.
How to grow Aubrieta
Aubrieta (often also spelt aubretia) grows in very similar conditions to Arabis, being happiest in full sun on well-drained alkaline soils that aren’t too rich. Flowering from early in the year often into late spring, they’re a fabulous splash of colour, from pale pink to vibrant violet, tumbling from cracks in walls or down slopes. Aubretias are incredibly low-maintenance, coping with drought and poor soils, and just need cutting back in the same way as Arabis once they’ve finished flowering to keep them from getting leggy.
Best cultivars to look out for
Here a
re a few of the most popular cultivars:
- Aubreita ‘Argenteovariegata’(AGM) - white-edged leaves and rich mauve-pink flowers.
- Aubretia ‘Doctor Mules’ AGM - first bred in the 1930’s and still popular today, with large vibrant violet-blue flowers.
- Aubretia ‘Red Cascade’ (AGM) - a mass of vivid red flowers in spring.
- Arabis alpina subsp caucasica ‘Schneehaube’(AGM), also called ‘Snowcap’ - a carpet of fragrant tiny white spring flowers.
- Arabis blepharophylla ‘Rose Delight’ - a gorgeous mat of scented purple-pink flowers in late spring.
For glorious spring colour, these charming and easy-to-grow perennials are hard to beat.
