Dark spur (lat. Delphinium) is a beautiful flowering perennial that can be found in many gardens with its mostly blue, violet or white flowers. If you cut back the spent shoots in summer, the plant will sprout again and bloom a second time in autumn.
What to do if delphiniums have faded?
As soon as the delphinium has faded, cut the panicles just above the leaves to encourage a second flowering in autumn. After fall blooming, trim the plant to just above the ground to prepare it for winter.
Prune larkspur after summer flowering
Most delphiniums bloom between June and July, although some varieties - this also depends on the location - show their flowers earlier or longer. But no matter when and for how long: As soon as the panicles of the summer flowers have faded, cut them off just above the leaves. As a rule, for many delphiniums this is between 20 and 30 centimeters above the ground. Under no circumstances should you cut deeper, as this will make it difficult for the plant to sprout again. With this cut you ensure that the bright colors of the delphinium shine again between September and November.
Leave the dead flowers on the plant for seed production
However, you should not carry out this cut if you want to collect the ripe follicles with the seeds in autumn. After the autumn blossoms, there is usually neither time nor energy for the plant to produce seeds. By the way, you now have to protect the cut delphinium from snail damage, for example by appropriate mulching, slug pellets (€9.00 on Amazon), snail traps or daily collection.
Cutting Delphinium after autumn flowering
That's why you can safely cut the delphinium back to just above the ground after the autumn flowering. Delphinium will sprout again in spring. Further preparation measures for the winter are basically not necessary, except that you can mulch the perennial heavily with compost and/or horn shavings after pruning. Any division should only be carried out after pruning - several days apart.
Tips & Tricks
The ideal day for pruning is a mild one with as cloudy a sky as possible. An old gardening saying says that plants can be moved and trimmed most easily on gray or even rainy days.
