The penstemon, of which there are several hundred species, is a mostly perennial, herbaceous perennial or perennial that was formerly counted among the figworts. Today, the plant, also known under the name Penstemon, is counted among the plantain family. In domestic gardens, this graceful plant is still relatively rare and when it is, then most often hybrid forms. This plant can reach heights of growth between 40 and 90 cm. Depending on the species, the Penstemon blooms between June and October, with the duration of the bloom largely depending on the respective location. The arrangement of the flowers is very similar to that of the foxglove. The showy inflorescences produce multiple hermaphrodite, five-petalled, bell-shaped flowers with an elongated calyx and are a brilliant shade of white, pink, red,
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The penstemon is very suitable for planting in the rock garden, for mixed perennial borders or for planting in beds. It can be planted in spring, but only after the ice saints, i.e. after May 15th. You can get young plants in gardening shops and plant them in the garden, or you can grow the plant from seeds indoors from the end of February.
The planting distance between the individual plants should be about 30 cm. When planting, depending on the species, the different growth heights should also be taken into account. Water well after planting. White astilbes, verbena, prunella or the edelweiss marguerite are particularly suitable as accompanying plants for the penstemon.
- The penstemon prefers fully sunny and warm locations.
- Partially shaded locations are also tolerated.
- The respective location should be protected from winds as much as possible.
- Otherwise, these dainty plants could easily snap over in stronger winds. Above all, the tall types of barbel are not particularly stable.
- Accordingly, it is advisable to provide them with appropriate supports if necessary.
Soil requirements can vary from species to species. While tall-growing species prefer permeable, nutrient-rich, not too moist and humus-rich soil, smaller species or dwarf forms feel more at home in poor, sandy soil. If necessary, the soil can be improved or upgraded by adding mature compost. Waterlogging should always be avoided. In order to avoid the formation of rot, it is advisable to make heavy soil more permeable with grit or coarse sand.
watering and fertilizing
The barbel should only be watered moderately and then the soil should always be kept slightly moist, especially if the drought persists. Fertilizing in spring at the beginning of the vegetation period with a commercially available complete organic fertilizer is usually sufficient. Additional fertilization of the barbel is then usually no longer necessary.
This plant does not usually have to be cut back, but you should cut off faded parts of the plant regularly. Incidentally, when the leaf thread has opened its flowers about 2/3, you can use it very well as a cut flower.
Most species of penstemon can survive winters that are not too cold with appropriate protection, because the penstemon is only conditionally hardy. Hybrids of the barnacle are usually the most sensitive to frost. In addition, the winter hardiness still depends on the respective variety, whereby newer breeds are now very well adapted to the climate in Germany. But even these plants cannot do without appropriate winter protection and can hibernate outdoors with protection.
For the overwintering of evergreen species, the affected plants should be cut back to about 20 cm and covered with fleece from October. In contrast, hybrids should be cut off close to the ground and covered with brushwood before the first frost if possible.
You probably have the best chance of getting this plant over the winter if you choose particularly frost-hardy plants when you buy it. One of these varieties is Penstemon barbartus ‘Coccineus’ and the most robust in terms of winter hardiness is the cultivar ‘Ansouvenir an Friedrich Hahn’.
Propagation by seed
The beard thread forms its seeds in numerous small capsule fruits. Autumn, but also spring, is suitable for sowing directly outdoors. However, the seeds should have been stored in the refrigerator for several weeks beforehand.
However, the plants can also be grown indoors in appropriate seed trays from February at around 15-18 degrees. To do this, they are scattered in seed soil and covered with a thin layer of vermiculite or compost. Then it is advisable to cover the planter with a translucent or transparent film.
At temperatures between 15 and 18 degrees, the seeds usually germinate after 14 to 30 days. The whole thing should not be too dark during this time. When the seedlings are large and, above all, strong enough, they can be pricked out or transplanted into small pots and cultivated in a slightly cooler place until they can finally be planted outside.
This is the case in late spring, as soon as no more night frosts are to be expected, usually not before the ice saints. When planting outdoors, you should ensure a distance of about 30 cm between the individual plants and then water the soil well.
propagation by division
- Division is the simplest and most uncomplicated form of propagation.
- Suitable times for this are both spring and autumn.
- If possible, the barbel should not be divided more often than every 2-3 years.
- To do this, the plant is carefully dug up and divided into several sections as required.
- Each individual section should have sufficient root system.
- Then the newly won plants can be planted in the garden.
Propagation of cuttings in pots or trays
Propagation from cuttings can be done throughout the growing season. The cuttings should preferably be cut from the plant in late summer.
The cuttings should be about 5-15 cm long and should always be cut below a leaf bud from the respective mother plant. Then the lower leaves of the cuttings are removed and placed in potting soil as quickly as possible. The substrate can also consist of a soil-sand mixture and the soil temperature should be between 20 and 25 degrees.
Now the whole thing is covered with foil or glass and the substrate is kept moist. The young plants should now be overwintered frost-free and only planted outside in the coming spring from mid-May.
Propagation of cuttings in foil
In addition to the propagation of cuttings in bowls or pots, there is a particularly space-saving method with black foil, for example with pond foil. To do this, cut an appropriately wide and long strip of pond liner and cover this about 3-4 cm thick with moss, which is then well moistened.
The cuttings are then laid out on this moss and the whole thing rolled up. The leaves of the cuttings should definitely look out of the foil. For a better hold you can then fix the whole thing with wire or something similar.
The foil with the cuttings is now placed in a flat container, eg a bowl, and placed in a bright place. Direct sunlight should be avoided. Now regularly fill the bowl with water so that the moss can soak up the water.
Then the cuttings are rooted at 15 to 18 degrees. If the cuttings are rooted, new leaves will appear after about 3-4 weeks. Now they can be carefully separated and planted individually in small pots.
- Penstemon ‘Remembrance of Friedrich Hahn’ – The dark pink to dark red flowers of this penstemon, which is only slightly frost-sensitive, are formed from summer to the first frosts. It grows about 75-80 cm high and about 60 cm wide.
- Penstemon digitalis ‘Husker’s Red’ – Bronze Penstemon – This penstemon is a very hardy variety, with a particularly attractive bronze-purple and evergreen foliage. The white, panicle-like flowers appear from July to August. An ornament are even the dark overflowing seeds, which are only formed later. This plant reaches heights of growth of up to 100 cm.
- Penstemon Hybride ‘Blackbird’ – Large Flowered Penstemon – This perennial variety has particularly dark and intense burgundy to deep purple flowers that appear from June to October. It grows to a height of about 60-70 cm and is conditionally hardy. Accordingly, appropriate winter protection is required.
- Penstemon barbartus ‘Coccineus’ – This fully hardy cultivar produces bright red flowers that appear from July to September. The growth height is between 80 and 100 cm. Winter protection is only recommended in particularly harsh locations.
diseases and pests
Plant diseases and pest infestation are less to be feared with the penstemon. Despite everything, rotting or infestation with powdery mildew can sometimes occur.
Root rot – The barbel tends to root rot often only in particularly moist clay soils. It is therefore advisable to choose a location with permeable soil for this plant or to improve its permeability with grit or coarse sand.
Powdery Mildew – Along with numerous other types of plants, the beard tongue can also be attacked by powdery mildew, a fungus. An infestation can initially be recognized by a white to gray mycelium or a mold covering on the upper side of the leaves. In the further process, the leaves wither, curl up and finally fall off.
Infestation occurs most frequently in autumn. The spread of this fungus is favored above all by warm, muggy weather and simultaneous strong temperature fluctuations between day and night.
In order to avoid spreading, the first step you should take is to remove and dispose of all weeds in the immediate vicinity of the infested plants, as well as obviously infested parts of the plant. In the event of an infestation in the greenhouse, the main thing to ensure is adequate ventilation.
As a preventative measure, fertilization that is too nitrogenous should be avoided. It is also advisable to decide on particularly resistant species when you buy them. To combat a severe infestation, the trade offers special fungicides that are sprayed or administered according to the manufacturer’s instructions.
The penstemon is a colorful perennial that is not yet found very often in domestic gardens. The right location is particularly important for this plant, which can have a significant effect on the flowering period. In order to be able to enjoy this flowering plant year after year, the right hibernation is a prerequisite, because the penstemon is mostly only partially hardy and would probably not survive stronger frosts without appropriate protection.