Mountain rockcress (Arabis alpina subsp. caucasica 'Schneehaube' SNOWCAP)

Overview

Mountain rockcress, specifically the cultivar Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP, is an exceptional choice for gardeners seeking resilient, early-spring color. This mat-forming, procumbent perennial creates a stunning drift of white flowers, earning it common names like Snowdrift in alpine settings. Its evergreen foliage provides texture interest throughout the year, contrasting nicely with the profusion of blooms.

The cultivar ‘Schneehaube’ SNOWCAP is valued for its dense coverage, typically reaching only about 7 inches tall but spreading to 18 inches wide or more, making it an ideal low-growing ground cover. As a variety of Arabis alpina subsp. Caucasica ‘Schneehaube’ SNOWCAP, it exhibits excellent tolerance for harsh conditions once established.

This rock cress offers significant practical benefits in challenging garden spots, thriving where many other plants struggle. It is particularly effective in rock gardens or cascading over retaining walls, offering an explosion of fragrant white flowers from April through June.

Fast Facts

• Plant Family: Brassicaceae
• Plant Type: Herbaceous perennial
• Hardiness Zones: USDA Zones 3-8
• Size at Maturity:
  • Height: 0.3-0.6 ft
  • Spread: 1-1.5 ft
• Bloom Time: April to June
• Bloom Description: White
• Sun Exposure: Full sun
• Water Needs: Dry to medium
• Maintenance Level: Medium

How to Grow

Plant Mountain rockcress in the spring or fall, ensuring it receives the full sun required for dense blooming. The most critical factor for success with Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP is ensuring perfect drainage; plant it in gritty or sandy soils. This strong-willed plant tolerates hot, dry conditions well once established and even performs adequately in somewhat infertile soils.

Water sparingly; allow soils to dry between watering sessions, as this plant prefers dry to medium conditions. Avoid overwatering, which is the primary cause of potential stress or root rot. Fertilization is generally unnecessary, as the species adapted to lean, alpine soils.

For best results, cut the foliage back after the main bloom period concludes in early summer. This pruning encourages a denser subsequent growth habit and keeps the tidy mat appearance of the evergreen leaves attractive through the summer months. Be aware that plants may decline faster when grown in summer heat south of Zone 6.

Propagation is straightforward, typically achieved either by sowing seeds or by simple rosette separation when dividing clumps. This ease of propagation adds to the overall value of using Arabis alpina subsp. Caucasica ‘Schneehaube’ SNOWCAP as an extensive ground cover.

Landscape Uses

Mountain rockcress excels as a ground cover, quickly forming thick, white carpets that suppress weed growth. It is perfectly suited for rock gardens, where the low habit allows it to nestle between stones, achieving a natural alpine effect. Consider mass plantings along border fronts or on dry, sunny banks where sharp drainage is assured.

The trailing nature of Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP makes it invaluable near walls or raised beds. Allow the foliage and spring blooms to cascade over retaining walls or the edge of steps, softening harsh architectural lines.

This perennial pairs well with other sun-loving, drought-tolerant alpines and rock garden inhabitants such as sedums, creeping thyme, and low-growing phlox varieties. Its early bloom period provides color before many summer perennials get established.

Standout Features

Flower Qualities

• Showy
• Fragrant

Noteworthy Characteristics

Arabis alpina, commonly known as mountain rock cress or alpine rock cress, is a mat-forming, tufted, procumbent, evergreen perennial of the mustard family that typically grows to 8-10” tall but spreads to 20” wide or more. It features loose spreading rosettes of toothed, obovate, gray-green basal leaves (to 2” long), shorter ovate stem leaves and tiny, 4-petaled, white flowers (each to 1/2” long) which bloom in spring. ‘Schneehaube’ SNOWCAP is a low-growing, mat-forming cultivar which reaches 7” tall with a 18” spread, and its evergreen foliage is densely covered in clusters of white blooms during the spring.

Tolerances

• Rabbit
• Deer
• Drought

Potential Problems

The primary issues pathologists note with Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP involve fungal diseases if cultural needs are ignored. White rust and downy mildew are common challenges, especially in humid conditions or where air circulation is poor. To manage these fungal issues, ensure proper spacing and avoid overhead watering late in the day.

Root rot is another significant risk, directly linked to poor drainage; if the soil remains saturated, the roots will fail. Always amend heavy soils heavily with grit or sand before planting Mountain rockcress. Beyond disease, gardeners should occasionally watch for common pests like aphids.

Frequently Asked Questions

What hardiness zones is Mountain rockcress suitable for?

Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP is reliably hardy in USDA Zones 3 through 8.

How large does Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP grow?

This cultivar typically achieves a height between 0.3 ft and 0.6 ft (about 4 to 7 inches) with a spread ranging from 1 ft to 1.5 ft (12 to 18 inches).

What sun exposure does Mountain rockcress need?

This plant performs best, providing the most profuse blooming, when given full sun exposure.

When does Mountain rockcress bloom?

The white flowers of Arabis alpina subsp. Caucasica ‘Schneehaube’ SNOWCAP appear relatively early, blooming from April into June.

Conclusion

Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP remains a staple for sunny, dry areas due to its easygoing nature and spectacular early spring flowering. The combined resilience and beauty offered by this Mountain rockcress make defining dry banks or rockeries simple. Always confirm your local garden zone compatibility before planting this tough alpine perennial.

Companion Planting

Cacti and succulents often make excellent companions for Mountain rockcress as they share the same critical requirements: intense sun and sharp drainage. Drought-tolerant ground covers like Creeping Thyme (Thymus serpyllum) or various Sedums cascade nicely alongside the low mounds of Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP, blurring the lines in a rock tapestry.

For color contrast after the white blooms fade, consider pairing this perennial with late-blooming bulbs or low-mounding Campanulas adapted to similar lean soil conditions. The gray-green foliage of Arabis alpina subsp. Caucasica ‘Schneehaube’ SNOWCAP also complements plants with deeper green or purple leaves.

Propagation Tips

The most accessible method for increasing your stock of Arabis alpina subsp. caucasica ‘Schneehaube’ SNOWCAP is through rosette separation. As the plant forms a dense mat, new daughter rosettes root easily along the trailing stems. In late spring or early fall, carefully sever these rooted sections from the parent plant and transplant them immediately into prepared gritty soil.

While propagation by seed is possible, maintaining cultivar purity can be difficult if natural cross-pollination occurs. If you choose to sow seed, surface sow the tiny seeds in gritty mix in early spring and keep the soil barely moist until germination occurs.