Penstemon cobaeae Wedding Bells

Sowing:

Sow Penstemon seeds indoors or in a greenhouse from February to April on the surface of good quality compost, covering them with a very thin layer of compost or vermiculite. Place the seed tray in a mini-greenhouse at a temperature of 15-20 °C, or in a transparent polyethylene bag until germination, which can take 1 to 4 months. Keep the compost moist but not waterlogged and do not exclude light, which promotes germination.

When the seedlings are large enough to handle, transplant them into 8cm (3in) pots in trays and grow the plants in cooler conditions. When all risk of frost has passed, gradually acclimatize them to outdoor conditions for 7 to 10 days before planting them outside. Space the plants 30cm (12in) apart. Choose a fertile, light, and well-drained soil in a sunny or semi-shaded position. Penstemons can tolerate dry soils, which encourage them to go into dormancy, but they dislike heavy soils that are particularly cold and wet in winter. Improve clayey and heavy soils by adding plenty of gravel or coarse sand before planting.

Cultivation:

To successfully grow hybrid penstemons, the nature of the soil is crucial. They prefer rather rich, fresh to dry, but very well-drained soils, especially in winter. In excessively moist soils, they rot quickly. In cool climates, place the plants in a warm and sunny position, sheltered from cold winds (south or west exposure). In hot climates, choose a cooler and semi-shaded exposure. In very cold regions, it is advisable to take stem cuttings in autumn. Penstemons do not have specific diseases. This plant requires only minimal maintenance, but when removing faded flowers in autumn, be sure to slightly shorten the flower stems without cutting them to the ground, especially in regions where winters are humid. Indeed, the foliage plays an important role in moisture regulation. Wait until spring is well established (March-April) to shorten branches whose foliage has been damaged by the cold. If it is dry in summer, water regularly to support flowering. In the coldest regions, cover the base with a glass or a cold frame to protect it from severe cold. Divide your penstemons every three or four years to rejuvenate them, but also wait until spring to carry out this operation.