Origin
Lewisia columbiana (T.J. Howell ex Gray) B.L. Robins. var. columbiana, commonly known as Columbia Lewisia, is a perennial flowering plant that originates in North America. It is native to the Pacific Northwest region of the United States and British Columbia, Canada.
Common Names
Columbia Lewisia is commonly known by its scientific name or as the Columbia bitterroot. It is also called the Siskiyou Lewisia, depending on the region it grows in.
Appearance
The Columbia Lewisia plant is a small, herbaceous perennial that typically grows to a height of 5 to 15 centimeters. The plant forms a basal rosette of succulent leaves, which are typically oblanceolate and have rounded tips. The leaves are 2 to 6 centimeters long and 1 to 2 centimeters wide. The stems of the plant are thin and naked, with pink to red flowers that bloom in early summer. The blooms appear atop a slender stalk that can grow up to 25 centimeters tall.
Uses
The Columbia Lewisia plant is primarily grown as an ornamental plant in gardens. It is often used in rock gardens, mixed herbaceous borders, or as a container plant. The plant requires well-drained soil and full or partial sunlight to thrive. Columbia Lewisia is a tough and drought-tolerant plant, making it an ideal plant in regions with dry summers. It is also an important plant for pollinators, as the flowers are attractive to bees and butterflies.
Light Requirements
Lewisia columbiana var. columbiana grows best under full sun exposure. It thrives in areas that receive at least 6 hours of direct sunlight daily and requires a minimum of 4 hours of sunlight per day.
Temperature Requirements
This plant prefers cooler temperatures and is well adapted to grow in alpine zones. It can tolerate temperatures as low as -10°C (14°F) and as high as 30°C (86°F). However, it thrives in temperatures ranging from 16°C (60°F) to 21°C (70°F).
Soil Requirements
Lewisia columbiana var. columbiana grows in well-drained, sandy or loamy soils with a pH range of 6.5 to 7.5. The soil should be moist but not waterlogged as this can lead to root rot. The plant requires good air circulation around its root system, so the soil must not be too compacted. It also benefits from applying a 5-10-5 fertilizer every spring.
Cultivation Methods
Lewisia columbiana (T.J. Howell ex Gray) B.L. Robins. var. columbiana, commonly known as the Columbia River Lewisia, is a low-growing perennial plant with small, succulent leaves, and showy daisy-like flowers. This plant grows best in well-draining, rocky or sandy soil, with plenty of sunlight and good air circulation. It is also cold-hardy, and can tolerate temperatures as low as -20°F.
To cultivate Lewisia columbiana var. columbiana, start by selecting a site with full sun exposure and well-draining soil. Amendment with sand, perlite, or other organic material may be necessary for heavier soils. The plant can be propagated by seed, division, or leaf cuttings, with the latter two methods giving faster results.
When planting, ensure that the depth of the plant is the same as it was in the original container or seedbed. Mulching around the plants can help to retain moisture, regulate soil temperature, and control weeds.
Watering Needs
Lewisia columbiana var. columbiana requires moderate water, especially during its growing season in the spring and summer. It is important to avoid over-watering, as this can lead to root rot and other diseases. A good watering practice is to wait until the soil is dry to the touch before watering the plant. Also, watering the plant in the morning is preferred as it allows the water to be absorbed fully before the higher sun intensity of the day.
During periods of drought, the plant may require more frequent watering. However, it is still essential to avoid overwatering. Using a well-draining soil mix and providing a 1-inch layer of mulch around the plant can help to conserve moisture. Adding a layer of gravel at the base of the plant's container can also promote better drainage.
Fertilization
Lewisia columbiana var. columbiana does not require fertilization, especially frequent use of synthetic fertilizers. Excess nutrients can lead to overly lush growth, which can compromise the plant's hardiness, and encourage disease and pests. However, you can use low-nitrogen fertilizers sparingly and only after a complete watering session or after rain.
If the plant's growth or flowering is suboptimal, organic soil amendments, such as compost, bone meal, or worm castings, can be used at most, once annually. The use of a controlled-release or slow-release fertilizer option can also offer continuous nutrition to the plant and minimize the chance of nitrogen or other micro-nutrient burn.
Pruning
Lewisia columbiana var. columbiana does not require extensive pruning, but the removal of dead flowers or spent flower stalks is highly advised. Doing this will promote continued blooming and sometimes lasting until autumn.
It is best to remove excess foliage or leggy growth in the early spring before the plant begins its growing cycle. Consequently, removing excessive ends can help to boost the plant's bushier habit. It is important to avoid cutting into the plant's foliage, which can lead to damage, disease, and complete loss to the plant.
It is also worth noting that Lewisia columbiana var. columbiana is a relatively short-lived plant. It may thrive for about three years before its flowering rates begin to reduce, and the plant eventually declines gradually. However, propagating the plant regularly can extend the plant's presence in your garden.
Propagation of Lewisia Columbiana
Lewisias can be propagated through various methods including seed propagation and vegetative propagation.
Seed Propagation
Seed propagation is one of the easiest ways to propagate Lewisias. The seeds of Lewisias should be sown in the fall or early spring. The ideal sowing time would be late April to early May. The seeds can be sown in flats or small pots with good quality potting soil. Lewisia seeds should be sown shallowly. Cover the seeds lightly and ensure that the soil is kept moist by covering the flats or pots with a plastic cover until the seedlings emerge.
Once the seedlings have emerged, remove the plastic cover and ensure that the seedlings receive enough light to grow. Young Lewisia seedlings require good air circulation and moderate moisture to thrive. After they have developed their second set of true leaves, transplant the seedlings into individual pots with soil that is rich in organic matter.
Vegetative Propagation
Lewisia columbiana can also be propagated through vegetative propagation. Vegetative propagation involves separating the plant into smaller sections and replanting those sections to grow into new plants. This method is ideal for mature Lewisia plants that have outgrown their current pots or location.
To propagate plants through this method, take the Lewisia plant and gently remove it from its pot. The plant should be gently separated into smaller sections and replanted in new pots with fresh potting soil. Water the newly propagated plants and place them in a location with good air circulation and moderate light. The replanted sections should root and continue to grow as individual plants.
Disease and Pest Management for Lewisia columbiana (T.J. Howell ex Gray) B.L. Robins. var. columbiana
Lewisia columbiana is a hardy plant species that is susceptible to a few common diseases and pests which can be managed through appropriate measures.
Common Diseases
Root Rot: This is one of the most common diseases that affects Lewisia columbiana plants. Root rot is caused by soil-borne fungi, and it leads to the decay of roots. Plants with root rot tend to wilt and have stunted growth. To manage root rot, ensure proper drainage and avoid over-watering. Use well-drained soil for planting and avoid waterlogging.
Powdery Mildew: Powdery mildew is a fungal disease that appears as a white or gray powdery substance on the plant leaves. It can lead to distorted growth and premature death of the plant. The best way to manage powdery mildew is to remove the affected leaves and to avoid overcrowding the plants. You can also use a fungicide spray to control the spread of the disease.
Leaf Spot: Leaf spots appear as brown or black circular spots on the plant's leaves. The spots may be surrounded by yellow halos, and they can lead to premature leaf drop. The best way to manage leaf spot is by removing the affected leaves and improving air circulation by avoiding overcrowding. You can also use a fungicide spray to control the spread of the disease.
Common Pests
Spider mites: Spider mites are tiny pests that feed on the plant's sap, and they may cause stunted growth and leaf yellowing. To manage spider mites, use an insecticidal soap or oil spray to kill the pests. You can also increase the humidity around the plant to discourage the pests from infesting the plant.
Thrips: Thrips are small, winged insects that can cause discoloration and distortion of the plant's leaves. You can manage thrips by using a systemic insecticide or by introducing natural predators, such as lacewings or ladybugs, to the garden.
Slugs and snails: These are common pests that feed on the plant's leaves and stems, leaving behind holes and damage. To manage slugs and snails, you can use physical barriers, such as copper tape or diatomaceous earth, or use baits to lure and kill the pests. You can also handpick the pests and remove them from the garden.
By being vigilant and taking appropriate measures, you can manage and prevent the spread of diseases and pests in your Lewisia columbiana garden.
