Delphinium & Achillea

Hi guys
I have grown some Delphinium & Achillea from seeds this summer and not sure if I need to plant them in the ground in the autumn or overwinter in their pots in the greenhouse (not heated) & plant in the springtime any advise would be welcome.

 

How big have they got? I prefer to plant perennials in Autumn, while the soil is warm from summer but they are usually larger plants, not seedlings.

 

I agree with Aaron, if the plants are big enough, get them in their final positions now.:gnthb:

 

Not sure how big is big enough but the Delps are in 5in pots with good roots & about 6 to 8 ins high. Achillea bit smaller in 3in pots but need to be repotted into bigger ones as roots coming out bottom of pot was going to repot this weekend. Do you think these will be OK to plant in ground maybe end of Sept?

 

I think the Achillea will be - they are tough and more importantly, the slugs and snails leave them alone. Once they get established, I find they need to be lifted and divided nearly every year to maintain them.

I don't do Delphiniums as the slugs like them even more than I do, so hopefully someone else will be able to advise, but they are classed as hardy perennials, so if they are bigger by the end of September, I would have thought they'd be fine. I know with Lupins, planting them in Autumn seems to harden them off sufficiently so they put on enough growth in Spring to counteract slug attacks.

 

As long as they have been properly hardened off I would get them in the ground on the weekend. I would treat with a liquid slug killer, this will give a few months slug protection.:gnthb:

 

What sort of liquid slug killer do you recommend David? I'm interested in that!

 

Slugit liquid.:gnthb::gnthb: