Penstemon x heterophyllus Blue Spring

The hardiness of Penstemon heterophyllus Blue Spring is moderate, withstanding temperatures as low as -9°C (15°F) as long as the soil is well-drained. It also tolerates summer humidity, again in well-drained soil. Once well-established, the plant can withstand periods of drought.

In order to successfully grow penstemons, the soil type is crucial. They generally prefer rich soil that is not too dry in the summer, but still well-drained. In excessively moist soil, they will quickly rot. In cooler climates, place the plants in a warm and sunny location, protected from cold winds (south or west exposure). In warmer climates, choose a cooler and partially shaded spot. In very cold regions, it is advisable to take stem cuttings in autumn.

Penstemons are not prone to any specific diseases. These plants require minimal maintenance, but when removing faded flowers in autumn, it is important to lightly prune the stems without cutting them back to the ground, especially in regions with humid winters. The foliage plays an important role in moisture regulation. Wait until spring is well-established (March-April) to prune any branches that have been damaged by cold weather. If the summer is dry, water regularly to support flowering. In the coldest regions, cover the base of the plant with 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 perform this operation.