Clypeola jonthlaspi: complete guide

Clypeola jonthlaspi, also known as disk cress, is a charming small plant belonging to the Brassicaceae family. This delicate species originates from South and Eastern Europe, with distribution extending to West Pakistan and the Arabian Peninsula. In temperate climates, this interesting plant can be cultivated in rock gardens or in dry, well-draining garden environments.

The plant grows very compactly, typically reaching only 15 to 30 centimeters in height. It forms a low, dense rosette of linear, greyish-green leaves. During spring, the plant produces tiny white flowers arranged in small clusters. These flowers are characteristic of the Brassicaceae family, featuring four petals.

Clypeola jonthlaspi has very specific growth requirements and thrives best in warm, dry climates. In temperate regions, the plant is best cultivated in an alpine house or in a sunny rock garden location with exceptionally well-draining soil. This plant prefers calcareous or neutral pH-valued soil and performs poorly in acidic conditions.

When planting, it is essential to use a very well-draining growing medium. A mixture of alpine soil, sand, and fine gravel creates an ideal growing medium. This plant cannot tolerate wet feet and does not tolerate waterlogging. A pH value between 4.5 and 5 is ideal for optimal growth, although the plant can also tolerate slightly alkaline soil.

Watering must be done carefully, especially during the growing season. Allow the soil to dry slightly between waterings, but ensure it does not dry out completely. In winter, water minimally, as the plant enters dormancy during this period. Excessive water inevitably leads to root rot in this sensitive little plant.

Feeding is not very important for this small plant. Minimal or no feeding is preferred. Excessive fertilizer can lead to luxuriant foliage growth without many flowers. If feeding is necessary, apply only very carefully a highly diluted solution during the growing season.

Clypeola jonthlaspi thrives best in full sun. The plant requires at least 6 to 8 hours of direct sunlight daily. In areas with very hot summers, some light afternoon shade may be beneficial, but in most temperate climates, full sun is recommended.

This small plant is not very susceptible to pests and diseases. In very humid conditions, however, fungi and rot can occur. Ensure good air circulation and avoid wetting the foliage to prevent fungal diseases. In very dry conditions, spider mites can sometimes become a problem.

Clypeola jonthlaspi is a plant for enthusiasts of alpine and slow-growing plants. The plant is very suitable for rock gardens, alpine troughs, Mediterranean-style gardens, and dry borders. In temperate regions, this plant is best cultivated in a protected environment or in very dry, sunny locations in the garden.

Reproduction can be done via seed, which should be sown in spring on very well-draining growing medium. The seeds are small and must be handled very carefully. Sowing should take place in a cold frame or in full sun outdoors, depending on your local climate.

This plant is winter-hardy in temperate zones and can overwinter outdoors, provided it is planted in very well-draining soil and protected from excessive moisture during winter. A layer of stones or gravel around the plant helps drain water and prevent rot.

Clypeola jonthlaspi is a plant for the true plant collector and for those who enjoy small, elegant alpine plants. It is worth the effort to integrate this interesting little plant into your garden or greenhouse. The delicate flowers and compact growth form make it an attractive element for alpine compositions. At specialty nurseries and plant shops, you may find seed or young plants when the season is favorable.