Here’s a drought-tolerant, but little-known, delight for rock gardens: Persian stonecress (Aehtionema scistosum). I fell in love with this plant; here is why:
It is easy to grow Persian stonecress in zones 4 through 8, which means it can take some cold and heat. Aside from the explosion of tiny pinkish-lavender flowers in spring, this little plant smells wonderfully fragrant. Ours grows at the edge of our patio, where we can enjoy its sweet scent. Other great features of this plant are that it is waterwise, evergreen and often re-seeds, creating a low mounded groundcover in a rock or alpine garden.
Where to Plant Persian Stonecress
For the fragrance, plant Persian stonecress where you sit or walk by and can easily bend down to enjoy its fragrance. Note that once it grows to maturity, the plant will reach nearly 10 inches high and 15 inches wide. Because Persian stonecress can naturalize or multiply, it can make a pretty spring groundcover up against rock borders.
Select a spot with full sun if possible and with soil that drains well. You can plant other groundcovers of different heights and bloom color nearby and they probably will grow to form a colorful groundcover in a few years. I love the look of ours butted up against yellow daisies.
How to Care for Persian Stonecress
Water a new plant a little more than you water other xeric plants, then water little to not at all. After the plant has finished flowering in spring, you can cut back the ends of the tiny branches to make it look neat. I leave the spent blooms on for several weeks or more. You also can trim the spent blooms off in fall; just avoid cutting into the evergreen part of the stems below.
Remove dead stems if necessary in early spring. Otherwise, wait for it to bud out as one of the first spring-blooming xeric plants. And as you clean up your garden in spring, watch for new plants that might have started nearby. Their needle-like foliage and rounded shape are easy to spot.
I am not certain yet how well Persian stonecress transplants; we moved one in spring because it was about to be covered up by a new planting area we were building (it had taken root in a rock border). The plant looked dried up, but has new growth at its base, so we hope it will be healthy and blooming in its new location next spring.
Add Persian Stonecress to Your Rock Garden
Persian stonecress is not a common plant in nurseries, but High Country Gardens, which specializes in drought-tolerant plants, carries it online and will ship it as a small potted plant. This is an easy and beautiful spring bloomer for any xeric garden.