The colour range can be seen in this bed of assorted Penstemons during mid-August.
Penstemons are a group of perennials – sometimes evergreen or semi-evergreen -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.
The Beardtongue flowers as they are commonly known, originate from areas of North and Central America, with a diverse range as to be expected from such a variety of locations. Habitats can range from dry scrubland through to high alpine plant situations.
They are grown for their huge range of colours, having open tubular or bell flowers, rising above the foliage on long stems clad in racemes or panicles of individual flowers all having a protruding ‘tongue’ from which the common name of Beard Tongue or Beardtongue plants.
Penstemons are easy-to-grow evergreen perennials and they really do brighten up the late summer and autumn garden and the evergreen types are not to be dismissed for giving a little winter cover and interest.
Penstemon flower colour range is from pure white through all shades violet, purple, pink and deepest red. Some flowers are attractively spotted on the inside and lip of the tupe – especially the beard or tongue!
Penstemon Port Wine: Penstemon Sour Grapes: Penstemon Alice Hindley
The foliage, though not spectacular, is attractive with lance shaped (lancolate) leaves and normally glossy dark green. The plants can individually be leggy or mostly clump-forming with spikelets of flowers, often held erect – sometimes more lax. The flowers resemble those of the Foxglove group - Digitalis – (Scrophulariaceae) and belong to the same family with the typical open funnel-shaped flowers.
Penstemon plants 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 Penstemon 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 mulch for protection in the coldest areas.
Like most perennials, they benefit from dead-heading after flowering – simply cut out the faded flower spikes – which will prolong the flowering season.
Early spring, trim back the damaged or wayward stems – back almost to ground level if required. If the plant has formed a bushy plant with no sign of winter harm, simply trim to tidy.
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!
Penstemons can be grown from seed – best sown in early spring in a heated propagator or greenhouse. Late winter is also ok.
Beardtongue plants 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.
The easiest way to increase stock is by division – best carried out in spring just as the plants are starting to re-grow after winter. 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.
Good Varieties of Penstemon include the following, but they are now being extensively hybridized with new varieties almost monthly – mainly from the USA.
P. Husker Red
P. Dark Towers – Deepest Red
P. heterophyllus – the Foothill Penstemon – Deep mauve – very floriferous
P. digitalis – assorted
P. Apple Blossom – Pink and white
P. Garnet AGM – Deep Wine red
P. Sour Grapes – Light mauve with striped white inners.
P. Burgundy Wine – deep red.
P. Alice Hindley AGM – Violet purple with white throat
Pests and diseases include eelworm