How to Grow and Propagate Penstemon and Points to Note
The stems of penstemon are fairly long, with leaves and flowers distributed along both sides of the stem. The flowers are commonly red or purple and are highly ornamental, making this one of the more popular flower varieties on the market today. Many people like to grow it, but most people are not clear about how to grow it.
How to Grow Penstemon
1. Soil choice. Penstemon cannot adapt to acidic soil, but it grows healthily in neutral or slightly alkaline soil. A fertile, sandy soil with excellent drainage, good aeration and lime content is best.
2. Light and temperature. Penstemon likes light and grows most healthily in an environment with ample light, humid air and good ventilation. However, penstemon is not heat-tolerant, so in summer do not provide shade at the right time to prevent direct sunlight from damaging the flowers and leaves of penstemon.
3. Watering: The soil used to grow penstemon must have good drainage. If grown in a pot, choose a flowerpot with holes in the bottom, and place some crushed stones under the pot to prevent the soil from becoming too wet, which would cause the roots of penstemon to rot.
4. Fertilizing: Pay attention to timely fertilizing penstemon before and after flowering, which can make its flowers large and brightly colored. After flowering, take cold-protection measures to help it overwinter smoothly.
Points to Note with Penstemon
1. Penstemon will produce a large number of clustered axillary buds and adventitious buds, the internodes become shorter, the leaves turn yellow and smaller, and clear veins appear. In winter the small branches do not fall off and take on a bird's-nest shape. Severely affected plants die that same year, while mildly affected ones also die after a few years. The disease is severe from July to August each year.
2. In spring, ring-barking the diseased branches can prevent the pathogen from transferring and spreading to other parts, achieving a control effect.
3. Penstemon is cold-tolerant and likes a cool, humid environment, so it is suitable for growing in the north. Then for friends in the south, as long as you provide proper shade, ensure good ventilation, and fertilize and water less, penstemon can still get through the summer safely.
How to Propagate Penstemon
1. Seed propagation. Sowing can be carried out when the temperature is 13-18°C, usually in autumn or early spring. Penstemon seeds germinate relatively slowly, so autumn sowing is often used. The seeds can be sown as soon as they are harvested, and they will germinate when the temperature reaches 18-21°C or above. During the growing period, apply fertilizer once every half month; either chicken manure or compound chemical fertilizer is fine. Note that seed propagation is more prone to variation, so many superior varieties generally do not use the sowing method.
2. Cutting propagation. Penstemon cutting propagation is also often carried out in autumn, and usually only superior varieties are propagated by cuttings. After penstemon finishes flowering, choose strong-growing tender branch tips, cut them into 10 cm lengths as cuttings, disinfect the cut ends, and insert them into the substrate. Keep up the humidity and provide proper shading, and they will root in about one month. Rooted plants can be potted and planted out. If planted in a flowerbed in the ground, they can be removed from the pots and divided in March or April after the ground thaws the following year.
3. Division propagation. Penstemon division propagation is generally chosen in spring. After the mother plant shows new buds, dig out the mother plant (with soil) within a few days, determine the new divisions based on the sprouts, cut the new plants away from the mother with a knife, and plant them directly. After planting, water thoroughly, and they can quickly expand their root system and grow into sizable plants.
Common Diseases of Penstemon and Their Control Methods
Clustered axillary buds and adventitious buds are a common disease of penstemon.
1. Symptoms: A large number of clustered axillary buds and adventitious buds, shortened internodes, yellowed and smaller leaves, and clear veins. In winter the small branches do not fall off and take on a bird's-nest shape. Severely affected plants die that same year, while mildly affected ones also die after a few years. The disease is severe from July to August each year.
2. Control methods: In spring, ring-barking the diseased branches can prevent the pathogen from transferring and spreading to other parts, achieving a control effect. In the early stage of the disease, spray a 4000-fold dilution of tetracycline antibiotics.
When planting penstemon, you must choose suitable soil, then control the temperature well, and sow at the right time. In the later stages of growing, you must strengthen the management of fertilizer, water and diseases. Only by doing this work well can penstemon grow vigorously.