As early as March, the dainty but extremely robust yellow whitlow-grass covers rocky locations with its bright yellow cushions of flowers.
Profile of yellow whitlow-grass:
Scientific name: Draba aizoides
Plant family: mustard family (Brassicaceae)
Sowing time: autumn
Planting time: spring
Flowering period: March to April
Location: sunny to partially shaded
Soil quality: stony to loamy, low in nutrients, low in humus
These information are for temperate climate!
Use in: planters, dry stone walls, natural garden, rock garden, potted garden
Winter hardiness: hardy, USDA Plant Hardiness Zones: 4 (-32 °C / -25 °F)
Bee and insect friendly: Yes
Plant characteristics and classification of yellow whitlow-grass
Plant order, origin and occurrence of yellow whitlow-grass
The natural occurrence of the yellow whitlow-grass (Draba aizoides) is limited to the mountainous countries of southern and central Europe to the Middle East. The evergreen perennial first colonized crevices and rock rubble of the alpine altitude. With the advance of the Ice Age over 10,000 years ago, it also migrated to the lower regions of the colline to montane elevation. The plant belongs to the mustard family (Brassicaceae). The taking of plants from nature is strictly forbidden, because it is an endangered species on the red list.
Characteristics of yellow whitlow-grass
In order to adapt to its alpine location, the yellow whitlow-grass remains very low with a growth height of 5 to 10 centimeters (2 to 4 in) and forms dense, spherical polster that consist of numerous rosettes. The delicate little plant survives the winter as an evergreen.
The about 2 centimeters (0.8 in) long, narrow leaves of the yellow whitlow-grass are grouped in dense rosettes. They have a leathery texture, which means they are perfectly adapted to their forbidding location in nature and also withstand winter. On the edge and partly on the top, they are covered with long hair that gives them a spiky look. The flower stems are leafless.
From March to April the plant develops its bright yellow flowers, which have four petals and reach a size of about 1.5 centimeters (0.6 in). Several individual flowers are combined to form a racemose, almost spherical inflorescence, which is carried by a short, leafless stalk. The flowers are a valuable bee-pasture. Their early flowering time is possible because the perennial prefigures its flowers in autumn.
As is typical for all mustard plants, the yellow whitlow-grass also develops pods. These form in autumn, are a maximum of 1.5 centimeters (0.6 in) long and only ripen in winter.
Yellow whitlow-grass – cultivation and care
The yellow whitlow-grass absolutely needs a sunny location.
The soil should be calcareous and well-drained. A sandy to loamy substrate interspersed with gravel or stones is well suited.
Spring is recommended as the planting time, so that the yellow whitlow-grass has enough time to take root before winter. The recommended planting distance is 15 centimeters (6 in).
The flower is very easy to care for in the right location, because cold, frost and snow cannot harm it. The only thing that troubles the delicate perennial is too much moisture in winter. As a preventive measure, you can set up a glass pane so that the root area is protected from water.
A regular division of the long-lived species is not absolutely necessary, but can be done if the clusters are too lush or if you want to propagate.
Yellow whitlow-grass can be propagated by sowing, but you should note that it need cold to germ. A propagation by division is also possible. To do this, it is best to dig up the polster after the flowering period and carefully separate some rosettes. It is important that the parts are rooted and that you plant them again immediately afterwards.
Diseases and pests
The tenacious yellow whitlow-grass is extraordinarily robust, alone stagnant winter moisture can cause problems for it and cause the polster and roots to rot.
The plant is hardy down to -32 °C / -25 °F. No special measures for the winter time are necessary.
Use in the garden
The dainty yellow whitlow-grass must be in a location that corresponds to its nature. Rock crevices and cracks in stone in the rock garden, tuff or stone troughs as well as wall crowns and cracks in dry stone walls are suitable. Colorful pictures result if you combine the yellow blooming of Draba aizoides with other perennials for the rock garden that bloom very early in the year. These include spring pheasant’s eye, pasque flowers, Alpine rock-jasmine, rock cress, lilacbush and evergreen orpine.