Lewisia, also known as bitterroot, scientific name Lewisia cotyledon, family Portulacaceae; genus Lewisia, native to the mountains of the central west coast of the United States. Its flower meaning is fairy-tale love. The flowers are white, blooming from early spring to summer. The roots are fleshy, and the leaves are obovate. Its cold hardiness is not strong. It likes moist spring and dry summer conditions. In humid climate areas, full sun is suitable. It prefers fertile, deep sandy soil. Propagation is by seed or by division in spring. It is used in rock gardens, and in recent years has become popular as a potted plant.
Growing Environment
In humid climate areas, full sun is suitable. Its cold hardiness is not strong. It likes moist spring and dry summer conditions. It prefers well-drained, deep, loose gravelly soil. It likes partial shade, but in humid climate areas, sunlight is suitable. It prefers fertile, deep sandy soil. It dislikes drought and is not tolerant of intense heat.
Cultivation Techniques
Propagation methods: seed propagation or division in spring.
The water used for sowing must be clean in quality, and the watering container must not be contaminated with oil, salt, acid, alkali, herbicides or other substances harmful to the seedlings.
In winter, when the soil temperature is very low, warm water may be used appropriately.
Division propagation: small plants form on the mother plant. The method of separating the small plants and planting them individually is called division propagation. This method is simple and has a high survival rate, but the propagation coefficient is relatively low, and it is often used for propagating superior individual plants.
Planting methods
(1) It is best before Qingming to use nutrient soil or leaf mold with a pH of 5.5-6.5; after potting, place it in a spot with half a day of sunlight, so that the leaves are green and the flowers abundant, otherwise it will be very difficult to bloom.
(2) Fertilization. Because Lewisia blooms relatively many times, it needs sufficient nutrients. From May it enters the growing period, so apply a fertilizer combining nitrogen and phosphorus 1-2 times; from June it blooms successively until October, and 1-2 times a month a phosphorus-based fertilizer should be applied as a top dressing, so that the flowers keep blooming continuously.
(3) Watering. In the hot midsummer season, the potting soil should be on the dry side and avoid wetness, to prevent root rot. Sometimes it will drop leaves, and in the following spring it will grow new leaves again.
(4) Pruning. At any time cut off dead branches, diseased branches, weak branches, overly dense branches and spent flowers and stems, to facilitate ventilation and light penetration,
For single-petaled ones, overly long and leggy branches should also be shortened, so that more side branches are produced and more flowers are borne.
(5) Cold protection and warmth. After winter begins, it should be moved indoors promptly and placed in a sunny, warm place, maintaining an indoor temperature of 3-5°C so it can overwinter; the potting soil should be on the dry side and avoid wetness, to prevent root rot. Sometimes it will drop leaves, and in the following spring it will grow new leaves again.
The propagation of Lewisia mainly includes cutting and layering. When taking cuttings, select robust 1-2 year old branches, cut them to about 10 cm, keep only the upper leaves and terminal bud, trim the base flat, insert into clean fine sandy soil, water thoroughly, cover with plastic film, and place under a shade shed; roots can form in about a month; layering includes air layering and ordinary layering. For air layering, the method of tying both ends of a plastic bag tightly can be used. It can survive in the same year.
Fertilization Management
① Lewisia needs certain nutritional conditions, otherwise it will grow and develop poorly and perform poorly in ornamental traits.
② For soil improvement, it is best to use a low-nitrogen fertilizer with a nitrogen-phosphorus-potassium ratio of 5:10:10 or organic matter, such as weed-free straw or lawn clippings, well-rotted compost or decomposed leaves, etc. In addition to increasing soil nutrients, this can also improve soil structure to promote the growth of beneficial soil microorganisms.
③ But be sure to avoid excessive fertilization, because this will favor weed growth and will also cause Lewisia plants to grow only leaves and bloom less.
Pruning and Tidy-Up
① After the peak flowering period, carry out simple work such as removing spent flowers and dead branches and leaves, to ensure the completeness of the landscape effect. In key areas, spent flowers should be tidied up at any time.
② To keep landscape flowers always showing a relatively good ornamental effect, they must be controlled so they do not set seed; generally during the seed-setting period, use a mower to trim them to a height of 10 to 15 cm. However, in some cases, in order to continue the landscape effect for the second year, a certain number of varieties should be allowed to complete the final seed-setting process, so that the seeds mature and fall off manually or naturally, and are spread evenly on the ground, for self-sowing and reproduction in the second year.
③ After the entire flowering period ends, before winter begins, water thoroughly one last time, cut off the withered aboveground parts, and according to individual needs appropriately cover with soil or non-woven fabric, plastic sheeting or other mulch, and wait for new growth in the following spring to enter the next growing period.