Overview
Arabis platysperma Gray var. platysperma, also known as the broad-seeded rockcress, is a flowering perennial plant that belongs to the mustard family. This plant is native to the western regions of North America, including Alaska, British Columbia, California, and Idaho. The plant grows in a wide range of habitats, including alpine meadows, rocky slopes, and dry hillsides.Appearance
Arabis platysperma Gray var. platysperma has a basal rosette of oblong to obovate leaves that grows up to 6 inches tall. The flowers of the plant emerge in spring and summer and are typically white in color, measuring up to half an inch across. They have four petals that are arranged in a cross-like shape. The fruits of the plant are elongated silicles, measuring up to an inch long, with flattened, wingless seeds that are about 2mm in size.Common Names
Arabis platysperma Gray var. platysperma is commonly known by several names, including broad-seeded rockcress, Sierra arabis, and large-seeded rockcress.Uses
Arabis platysperma Gray var. platysperma is mainly used for ornamental purposes in rock gardens, alpine gardens, or as an edging or groundcover plant. The plant's leaves are sometimes used as a mild salad green and can also be cooked and eaten as a potherb. Some Native American communities used rockcress medicinally to treat various ailments, including intestinal worms and skin irritations. In conclusion, Arabis platysperma Gray var. platysperma is a beautiful and versatile plant that has both ornamental and medicinal uses. Its impressive white flowers and broad basal leaves make it an excellent addition to any garden or landscape.Light Requirements
Arabis platysperma Gray var. platysperma thrives in moderate to full sunlight. Plants grown in areas with inadequate lighting will exhibit elongated and compact growth habits as they struggle to reach the sun. Conversely, plants exposed to too much sun may experience leaf scorching or wilting.
Temperature Requirements
The plant is most suited for cool to mild climates, as it prefers temperatures ranging from 55 to 65 degrees Fahrenheit. The ideal temperature range for its growth is between 60 and 65 degrees Fahrenheit. Growth slows or stops entirely at temperatures above 75 degrees Fahrenheit, and at <50 degrees Fahrenheit, plants may suffer from damage or death. The plant can tolerate minor fluctuations in temperature for a short period, but extreme temperature changes can adversely affect growth rates.
Soil Requirements
Arabis platysperma Gray var. platysperma prefers well-draining, moderately fertile soils. Roots can develop deeply, so the depth of the planting site should be at least six inches. The plant can grow in different soil types, including sand, loam, and silt, but it cannot develop in heavy clay or waterlogged soils. It is also highly adaptable to soil pH and can grow in either acidic or alkaline soils.
Cultivation
Arabis platysperma Gray var. platysperma or coastal rockcress is an alpine plant that requires well-drained soil, with a neutral to slightly acidic pH (between 5.8-7.0). It thrives in full sunlight and prefers cool and moist environments. Therefore, it is essential to choose a location that gets plenty of sun and has good drainage to grow this plant successfully.
Watering Needs
Coastal rockcress is a drought-tolerant plant, and it can survive long periods without water. However, in hot weather or dry conditions, you should water it regularly. Make sure the soil is uniformly moist but not soggy. The best way to water this plant is to provide it with at least one inch of water per week, either through rainfall or manual watering.
Fertilization
Arabis platysperma Gray var. platysperma is a low-maintenance plant that doesn't require much fertilization. However, providing it with nutrients will help it to grow better. You can fertilize your coastal rockcress once every three months with a balanced fertilizer that contains nitrogen, phosphorus, and potassium. Alternatively, you can add compost to the soil to enrich it naturally.
Pruning
Pruning is not necessary for coastal rockcress. However, you can trim back the plant after flowering to stimulate more growth or help to maintain its shape. When pruning, remove spent blooms and old stems from the base of the plant. This will encourage new growth and help to keep your plant healthy and vigorous.
Propagation Methods for Arabis platysperma Gray var. platysperma
Arabis platysperma Gray var. platysperma, commonly known as the roundfruit rockcress, is a herbaceous plant native to North America.
One of the easiest ways to propagate Arabis platysperma is by root cuttings. Take a cutting of a healthy root and plant it in a container filled with moist soil. Keep the soil moist until the cutting has established roots, which usually takes several weeks.
Another propagation method for Arabis platysperma is by division. This is best done in the spring or fall, when the plant is not actively growing. Gently dig up the plant and divide the root clump into smaller sections. These sections can be planted in new locations or containers.
Arabis platysperma can also be propagated by seed. Sow the seeds in a well-draining soil mix and keep the soil moist until the seedlings emerge. Transplant the seedlings into individual containers or into the garden once they have a few true leaves.
Overall, Arabis platysperma Gray var. platysperma is an easy-to-propagate plant that can be propagated by root cuttings, division, or seed.
Disease Management
Arabis platysperma Gray var. platysperma is relatively resistant to diseases. However, they can still be prone to the following common fungal infections:
- Downy mildew: This disease causes yellow patches on the leaves. To manage downy mildew, ensure good plant spacing, avoid overhead watering, and remove any infected plant debris.
- Anthracnose: Symptoms of anthracnose include the formation of sunken, reddish brown spots on leaves. If you notice any signs of anthracnose, remove any infected plant parts, and dispose of them correctly.
- Botrytis: Botrytis is a grey fungal mold that grows on young and old leaves. To control botrytis, avoid overhead watering, increase plant spacing and remove any infected plant debris.
Pest Management
Arabis platysperma Gray var. platysperma is generally pest resistant, but they can still be affected by the following pests:
- Aphids: These small insects suck the sap from leaves and stems. Remove any aphids from the plant using a steady stream of water or by using insecticidal soap.
- Slugs and snails: These pests can chew holes in leaves, leaving behind a slimy trail. To manage slugs and snails, sprinkle diatomaceous earth around the base of the plant or handpick and dispose of them.
- Cabbage loopers: The cabbage looper is a green caterpillar that can cause damage to the leaves. To manage cabbage loopers, handpick and remove the caterpillars, and use a Bacillus thuringiensis (Bt) insecticide if the infestation is severe.
