Origin
Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz, also known as Lemmon's mustard, is native to California and can be found in the central and southern parts of the state.
Common Names
Lemmon's mustard is the most common name for this plant. Other colloquial names include Coulter's jewel flower and San Diego jewel flower.
Uses
This plant has had a variety of traditional medicinal uses by Native American tribes in California, such as being used as a poultice to treat burns and swelling. Additionally, Lemmon's mustard has been used as a food source--as a spice, a green vegetable or as a seasoning--by the same tribes. The plant can also be used in landscaping and gardening as it is drought-tolerant and low-maintenance.
General Appearance
Lemmon's mustard is a flowering herbaceous plant that can grow up to two feet tall. The leaves are narrow, with a toothed edge, and have a bluish-green color. The plant produces yellow flowers that grow in clusters at the end of long stems and bloom from March to June. The fruit produced by the plant is a long, slender, and pointed pod that contains many small seeds.
Light Requirements:
Caulanthus coulteri S. Wats. var. lemmonii typically grows in full sun to partial shade. It can tolerate some shade, but it grows best in areas with at least 6 hours of direct sunlight a day. Lack of sufficient sunlight can lead to poor growth and reduced flower production.
Temperature Requirements:
This plant is native to the southwestern United States and can tolerate hot and dry conditions. It grows well in USDA hardiness zones 8 through 10, which have average annual minimum temperatures between 10 and 40 degrees Fahrenheit (-12 and 4 degrees Celsius). It is important to note that this plant may not thrive in areas with frequent freezes or extreme heat waves.
Soil Requirements:
Caulanthus coulteri S. Wats. var. lemmonii prefers well-draining soils that are rich in nutrients. It can tolerate a wide range of soil types, but it grows best in sandy or loamy soils with a pH between 6.8 and 7.5. This plant is adapted to arid conditions and can withstand drought, so it is important not to overwater it.
Cultivation
Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz prefers to grow in well-draining soils that are slightly alkaline. To cultivate this plant, you need to start by identifying a suitable location that has full exposure to sunlight as it needs plenty of light for proper growth and development. Plant the seedlings in the soil at a distance of about 6 to 12 inches apart.
Watering Needs
The watering needs of Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz are relatively low, and it is essential to avoid over-watering, which can lead to root rot. Allow the soil to dry out partially between watering sessions and make sure the soil is moist but not too wet. Check the soil moisture levels before watering the plant.
Fertilization
When fertilizing Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz, it is crucial to use a slow-release fertilizer that comprises a balanced ratio of nitrogen, phosphorus, and potassium. Apply the fertilizer during the growing season, which usually runs from spring to fall. Avoid fertilizing the plant during the winter when it becomes dormant.
Pruning
Pruning Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz is not necessary as it is a self-cleaning plant, which means that the dead flowers and foliage naturally fall off. However, if you want to tidy up the plant or control its size, you can prune it back in the late fall or winter when it goes dormant. Cut back the plant by a third of its size, removing any dead, diseased, or damaged growth.
Propagation of Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz
Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz, commonly known as Lemmon's jewelflower, can be propagated through several methods:
Seed Propagation
One of the most common methods of propagating Caulanthus coulteri S. Wats. var. lemmonii is through seeds. The seeds can be collected from fully matured flower buds. The best time to collect the seeds is when the pods turn brown and dry. The pod should be collected and left to air dry until it splits open, revealing the seeds inside. To increase germination success, stratification or cold treatment of the seeds for 4-6 weeks is recommended before sowing. The seeds can be sown in well-draining soil, kept moist and in a shaded area until the seeds establish themselves, which usually takes about 2-4 weeks.
Cuttings
Caulanthus coulteri S. Wats. var. lemmonii can also be propagated through cuttings. Cuttings are taken from the mother plant in the spring or summer months when the stems are young and green. The cuttings should be about 4-6 inches in length and should be taken from the tip of the plant. The leaves on the lower half of the stem should be removed, leaving only a few at the top. The cuttings can then be placed in a well-draining soil mix and kept moist. It is recommended to cover the cuttings with a clear plastic bag to create a humid environment which will help to encourage root growth. The cuttings will usually root in about 4-6 weeks.
Division
Division is another method used to propagate Caulanthus coulteri S. Wats. var. lemmonii. This method is best done in the early spring as soon as new growth appears. The plant can be carefully dug up and divided into several sections using a sharp knife or garden fork. Each division should have several healthy roots and a stem with leaves. The divisions can then be replanted in a well-draining soil mix and kept moist until they establish themselves.
Disease Management
Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz is susceptible to fungal diseases such as powdery mildew, downy mildew, and root rot. Crop rotation, avoidance of overhead watering, and planting disease-resistant varieties can help prevent fungal diseases from spreading.
To control powdery mildew, apply fungicides containing sulfur or potassium bicarbonate. For downy mildew, use copper-based fungicides. For root rot, practice proper irrigation and drainage and avoid overwatering. Soil drenching with fungicides such as thiophanate-methyl can also be done.
Pest Management
The most common pests that affect Caulanthus coulteri S. Wats. var. lemmonii (S. Wats.) Munz are aphids, caterpillars, and flea beetles. To control aphids, use insecticidal soaps or oils, neem oil, or pyrethrin. Beneficial insects such as ladybugs, lacewings, and parasitic wasps can also be used to control aphids.
Caterpillars can be controlled by handpicking or using Bacillus thuringiensis (Bt) insecticides. Flea beetles can be managed by using row covers or applying insecticides like carbaryl or neem oil.
Regular inspection of plants is essential to detect pests early. It is also important to maintain a healthy growing environment by removing weeds, dead plant material, and regularly fertilizing the plants.
