At this time of year, Delphiniums stand in the garden like rockets or fireworks that have left their blazing trail standing in the air, they are the most vigorous verticals the summer garden can provide. Eremurus and Foxgloves are more delicate, making less of a solid block, but the density of Delphinium colour is their great contribution.
How To Get A Great Display
To have Delphiniums looking good requires a bit of TLC. They love well-drained soil, but are hungry feeders. This means adding plenty of grit on heavy soils to help with soil drainage. If Delphiniums sit wet in their dormant winter season, they can die, so make sure you prevent this.
They also need plenty of organic matter added to their planting holes when they first go in, then regular feeding throughout their growing season. You want to use something slow release – blood fish and bone, or a scattering of bone meal. Do this a couple of times in summer and try to repeat once in autumn before the plants die down.
Pests And Diseases
Delphinium shoots break through the ground in March and if you don’t watch out, slugs can have every one. That’s the moment for your nemaslug, or a dose of garlic.
Garlic drench – Make your own with two crushed garlic cloves added to two pints of water. Boil for half an hour and then strain off the liquid and bottle. Plastic milk cartons are good. Keep the liquid in a cool place and once a week, in their early growing season of March and April, dose your plants from a watering can. Add two teaspoons of drench to one gallon of water and water the plants and a good circle of soil around them.
In a dry year, Delphiniums can suffer from powdery mildew. For prevention, plant your plants widely and thin out the shoots emerging from the crowns early in the year to allow for air circulation.
There is also an organic treatment for mildew based on washing powder. Mix up one cup of bicarbonate of soda with one cup of automatic washing powder in a bucket of water. Then mix a cup of that in one gallon of water and use to douse your plants once every couple of weeks to keep mildew at bay. The washing powder helps the mix stick and the bicarbonate burns the mildew.
Staking And Support
Delphiniums ned staking as any strong wind or heavy rain will flatten them and break their hollow stems.
As Cut Flowers
For a wonderful June/July treat, fill at least one vase with cut flowers. If you are brave enough to pick them, you want the flowers to last as long as possible.
To guarantee that they stay looking good for at least a week, fill the hollow stems with water, put your thumb over the end of each one and lower them into a vase full of water. The stems last well, with the individual flowers even at the tip of the spike lasting at least a week.