Dowdeswell's Delphiniums has had a Company Forum page for 5 weeks or so but I'm finding it really difficult to start any conversations about growing these plants so I'm repeating my last post on the company forum page in this perennials forum. Perhaps this is the best place for it anyway. What we're trying to do is to glean information about how delphiniums are grown across a range of climates, what problems are faced by gardeners and how these are overcome. We will then, with permission, add this information to that already on our web site. The aim is to have as comprehensive a range of growing information available to gardeners as possible - but for this we need your input. Who's game?
There's also a bribe - a free packet of hybrid delphinium seeds to anyone who contributes.
Who sprays their delphiniums? What with?
Delphiniums attract few pests and diseases. Some folk have problems with army caterpillar and slugs can be a problem early in the season, but neither of these pests are likely to devastate the plants entirely. Careful inspection for caterpillars in the spring can prevent the majority of damage from cut worms. If molluscs are likely to be a problem then placing a few slug pellets actually on the crown of the plant in fall and again a couple of times in very early spring should deal to these. Mulching with something sharp like sawdust will help keep them away too. Do remember though, slugs like delphiniums just as much as hostas, which is a lot. Always put slug pellets down before you plant new delphiniums.
Powdery mildew is minimized by keeping the plants well fed, watered and mulched. Remember to give them plenty of space too, so that the leaves have air around them. Warm, humid weather encourages the disease so make a pact with your local weatherman! A healthy New Millennium Delphinium rarely gets powdery mildew. SA sulphur based preventive spray applied when the plants are six inches tall, again when knee high and maybe once more as the flower spike forms will go a long way to preventing powdery mildew
So, who has problems with pests and diseases in delphiniums? What do you do and what would you advise gardeners in your area? Any takers?