I can't claim rousing success growing them, even via winter sowing, but I do have a gallon pot of delphs on my breezeway that's in its third year without disappearing. If it weren't for that last hold-out I'd have given up four years ago. I have ideal soil & light conditions to grow them and would very much like to stumble onto whatever I've done wrong in years past. I have no clue why the gallon pot on the breezeway is still going strong three seasons later.

My best guess is that August isn't the ideal month to plant any perennial since the chance of intense heat even in Zone 5 is always a worry. The cooler temps in September/October allow the plants to establish roots before the ground freezes.

My 'Perennials for Every Purpose' book comes with this warning: Think Twice - they need constant attention. I'm much more of a 'Plant it & forget/just enjoy it' gardener.'

I'm compensated for the lack of delphs in my garden beds by substituting balloon flowers which are very hardy, bloom in late summer & are a lot less temperamental.

Delphiniums need good drainage, are heavy feeders and don't like heat. Do you have a spot that gets dappled sunlight? A favorite area for me here in this climate (summers often hot) is on the east side of the house. They can take the morning sun yet appreciate the afternoon shade.

In previous years I had no problems growing delphinium and considered them easy but this year has been different. It's been very hot and dry and because I was away and also have had a few personal problems my garden has not had enough water or care. My delphs have now been cut way back and look awful but I hope they survive. Most of mine are very old, well past their prime as they are not long-lived perennials. They are well over 10 years old so perhaps they have had their time. I do have a few new ones that have come up nearby and have successfully transplanted them but will try to keep the old ones going as long as possible.

To amend soil I prefer compost and also always use alfalfa tea or pellets. With young plants I think it's a good idea to cut off the blooms so they aren't putting out extra energy in flowering. However I don't always do that even if it's a good idea! If your plants are not root bound they can stay in pots in a semi-shady spot until you can amend the soil and the temps are cooler. Try to put them in a permanent place as they don't like to be moved and can get quite large so give them enough space.

Hope you have better luck with these pretty plants.

Here is a link that might be useful: Longevity of perennials

Planted them this evening, suppose to get rain overnight. I did bring up some good dark soil from the compost pile and shoveled that in the area I was going to plant them, then did some back fill with the same when I was planting. Then mulched with leaf mulch. This area is up against the house off the back porch, in a corner of sorts, gets nice morning sun only and adequate moisture. I've been amending the soil there for the past three seasons, so we shall see what happens. I have foxglove that were gifted me in the Spring planted there also. They did surprisingly well.

Gosh, I thought about snipping off those blooms but didn't have the heart. lol

They are supposed to like alkali rather than acidic soil too. And the "heavy feeder" is for real too. If you want to, look on the Graceful Gardens website. They have a really good article about delphiniums.
kay

Thanks kitten, I went to the site and read the article. Good info. Manure huh? I have lots of farmer friends, I wonder if I should rake off the leaf mulch, put a layer of old manure (not fresh) down now, then put some leaf mulch back on.

So by "heavy feeders" you guys/gals mean compost and such, not necessarily commercial fertilizers?

I'm in zone 5 and can plant delphiniums in summer if I want.. The key is always to water your plants before transplanting. Do not fertilize any new transplants and most definitely not at the height of summer. keep the plant moist (but not flooded). That should do it. the location of my delphiniums had been in my south facing yard (so strong sunlight). But I removed the plants after a few years to make way for other plants.

I would say that plants placed near the house can suffer from lack of moisture and too much heat. All these factor in the plants survival rate.

No need to remove the leaf mulch. But add the composted manure maybe sometime late in August when the sun is more forgiving (lest you might cause a nitrogen burn)...

I don't really rely on commercial fertilizers but it's a personal preference. I prefer adding composted manure early in the season.

Ianna