Penstemons. How to grow and care for this versatile group of plants. 

Penstemons are a group of perennials which are deservedly popular. They flower in the later part of the year, but are usually showing colour by end of July – or a little earlier. There is a huge range of colours in Penstemons, they are easy to grow, they are perennial and they really do brighten up the late summer and autumn garden. Penstemons can be grown in a border, a bed, or even a container. All they require is reasonable soil in which to grow. They are relatively drought tolerant, and whilst Penstemons are happy in full sun, they will tolerate a degree of shade as well.

They are mid height - from 18 - 30in, and may need a little support from a few birch twigs or similar plant support.

They are generally hardy, but are not too happy in wet soil in a cold winter! The dormant plant is best covered with a mulch for protection in the coldest areas.
Like most perennials, they benefit from dead heading – simply cut out the faded flower spikes – which will prolong the flowering season.

Propagation

•  Penstemons can be grown from seed – best sown in early spring in a heated propagator or greenhouse. Late winter is also ok.

• Penstemons can be grown from softwood cutting in summer, or semi ripe cuttings in late summer. You can start taking cuttings in august – and continue to do so until end of October. They can be potted up once rooted, BUT the young plants will need care through the winter – preferably in a frost free greenhouse.

• Penstemons can be divided in the spring.

Penstemons are contagious! Once you have a plant and are able to see their value in terms of colour and ease of maintenance, you are almost sure to seek out others.

Growing Conditions
 

• Penstemons are best in a slightly alkaline (non-acid) soil.

• Well drained soils are best. Raised beds are perfect. Incorporate plenty of coarse sand/grit into the planting hole.

• They rarely require feeding – an annual organic mulch in winter or spring is enough.
  The form of the leaf is usually an indication of the particular variety’s winter hardiness. The narrower leaved varieties of Penstemons are normally the hardiest!

• Pests and diseases include eelworm, slugs and snails, and powdery mildew.

 

 
The colour range can be seen in this bed of assorted Penstemons during mid-August.

 
Penstemon Port Wine:         Penstemon Sour Grapes:     Penstemon Alice Hindley