For the summer and the winter
Published 14/07/2015 | 00:00
dead-head your roses as they finish flowering
Deutzia setchuenensis corymibiflora
Penstemons have long been a favourite plant of mine and I tend to use them in most garden plans I draw. And here's the reason. They are pretty, undemanding and repay you by the bucket load. Bucket loads of flower.
A great favourite in the late 1800s and early 1900s, they were used extensively in summer bedding schemes. Between the wars they fell out of fashion. This was in part because Penstemon had the reputation for not being totally hardy. That was largely down to the fact that they were hard pruned to the ground in winter. The hard pruning was fine as it encourages more spring growth and more flower stems. But by pruning in winter it left the roots exposed to the worst of the winter elements.
So the rule is leave pruning Penstemons until mid March, they tend to stay evergreen so are quite welcome during the winter months for their foliage as well as their summer flowers. To hard prune cut back to within six inches of the ground. By mid March you can usually see the new growth sprouting from the plant base. This will help convince you that you are not about to commit plant homicide.
Planted in a sunny or partially shaded position in well drained prepared garden soil Penstemons will flower from late June right up until the first cold spell, possibly as late as mid November. One thing you must do to ensure this is to regularly deadhead the old flower stems. Without this the plant runs to seed, thinking its propagation job is done for the year. By taking off the old flower stems before they set seed the plant will be induced to produce more flower. Most Penstemon are around 60cm high and all have trumpet shaped flowers.
You will find Penstemon in flower in garden centres well into autumn but if buying then it is better wait and plant them in the spring.
Leave the plant in the pot somewhere sheltered until late April when they will be vigorously growing. Feed annually with a general garden fertiliser as a minimum. A manure mulch in February won't go astray and I give mine a foliar feed every month during the growing season to help them along. They will however perform admirably even if neglected somewhat.
When pruning in March have a look for rooted side shoots. These occur when a stem of the plant is touching the soil in the summer and has set roots out. This is call layering and gives you free plants. Snip the connecting shoot from the parent plant and carefully dig up. Pot up to grow on for planting out in June. Cuttings are also easily taken at this time of year.
The colour range of Penstemons is white, pink, red and purple. Some are called blue but I find these very insipid and washed out looking. Some are larger flowered than others. The smaller flowered varieties tend to be more wispy as plants which has its own charm.
Some named varieties in the large flowered category are White Bedder' now sometimes called 'Snowstorm' which is pure white. 'Osprey' is apple blossom coloured. 'Burgundy' is a deep wine red, 'Raven' is very similar. 'King George' is brilliant red with a white throat'
Smaller flowered varieties include 'Evelyn' pink and dwarf in size with willow thin leaves. 'Garnet' is a soft red and the hardiest of all and 'Sour Grapes' is a silvery blue. Whichever you choose you won't be disappointed.