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Perennial Planting

My free perennials (Delphinium, Geum, Campanula and Coreopsis) are doing really well and last night I repotted them (although they do look a little sad this morning, they didn't like moving home!!).  I am not sure when to plant them out, all the info says 'when big enough' but how big is 'big enough'??  I was going to wait until they have filled the pots they are in now (square 10cm) and then plant them out, by which time it will be June and no risk of frost.

Would the experts amongst you say this is right? 

Also, I am not expected flowers this year, again is that right or might I be lucky and get some flowers?

Thanks.

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Posts

  • Busy Bee2Busy Bee2 Posts: 1,005

    Mine went out about this time last year with the obligatory bottles on till June.  Essentially, as perennials they are by nature hardy, but it is really an issue of you wanting to get the roots to develop this year for a proper good display next year, so if you are keeping them in pots on a hardening off table, the main advantage would be that they are less likely to get nibbled by snails, slugs, birds etc.  I had some delphinium seedlings in the greenhouse which were in pots - quite a reasonable size, but I moved them out because my gut instinct was that it was getting too warm in there for plants which are essentially hardy.  They seem happier spending 24 hours on the hardening off table.  I could put them in the border under a bottle, but I wonder whether on the really hot days we have had, they might again find themselves sweltering.  So for now, the table seems as good a spot as any, with the proviso that I should keep checking the roots and pot on rather than let them get pot bound, as it is the roots that matter this year.  The bigger they are when you plant them out the less prone to snail attack - not least because the later in the season the tougher they will be and the more likely that the snails will have something else to eat.  But just don't let the roots suffer, and give them some growing time in their final position this year so that the roots can acclimatise to your soil before winter.  Lots of sun for the delphiniums in my experience.  They do really well here in one bed, and I have wanted to put an echo in the diagonally opposite bed, which gets less sun, and I have given up trying now - they never take.  The geum and coreopsis flowered last year, but are much bigger this year.  Never had much luck with campanula, but am growing from seed now - they will go in a very sunny bed for next year, and maybe will like that. 

  • Jim MacdJim Macd Posts: 750

    How big depends where they're going, if you're going to give them lots of space and look after them, then plant them sooner. If they're going to have to fight it out then plant them only when they're in a 1 litre pot or bigger if it's really crowded with aggressive neighbours. I planted plugs of cowslips in grass three years ago. They are only a little bigger now than when they went in. Where as ones I left in pots and potted on for one reason or another are huge.

  • Dave MorganDave Morgan Posts: 3,123

    Leave them in pots till the roots fill the pot, not pot bound, but a good root system. Then plant and trim them down by half, this will encourage the roots to establish and they will flower well next year. The bare root perennials you buy are usually 2 year old plants so they can flower this year, but I find letting them establish first gives you a stronger plant the following year, and Busy is right keeping them away from slugs and snails gives them more chance to resist the  damage they can cause.

  • Busy Bee2Busy Bee2 Posts: 1,005

    Dave, I shall follow your advice then with my delphiniums - trimming down, unless you think that as seedlings they wouldn't cope.  Never thought about cutting back the foliage.  Should have done that with my stuff last year probably.  Thanks - that's useful to know.  And while we are on, I'm very excited about the fact that I've grown some verbascum from seed, and am going to stick it in a nursery bed - would you chop the foliage on those this year and stop them from flowering?  I planted them at the later end of the planting period and they are plug sized now, but it did say on the packet that they can flower in the first year. 

  • fidgetbonesfidgetbones Posts: 17,617

    The coreopsis I had last year flowered  but didn't survive the winter. The others I would expect to flower next year. The delphiniums I would pot on to bigger pots, keeping them slug free. In the ground over winter, they are unlikely to survive the slug onslaught.

    The geum and campanula  I would plant out when the roots fill the 10cm pot.

  • Orchid LadyOrchid Lady Posts: 5,800

    Thanks everyone.....I will read through the comments again later when having 'quiet time' and make notes but I think I know what I'm doing now image

  • Dave MorganDave Morgan Posts: 3,123

    Busy, if your delphiniums were sown this year then leave them develop. I doubt they will throw up a flower spike this year, but if they do then cut it out and plant them in their flowering position in the autumn. Verbascum can flower in the first year if sown early enough, but again unless you are in a hurry cut out any flower spike and plant them in the autumn again. Most people make the mistake of planting perennials when they come into the GC's and shops, but autumn is always the best time to plant anything except bedding. Planted in September when the soil is still warm lets them establish and as soon as the warmer weather arrives the following year, they get off to a far better start as they are much stronger.

  • Jim MacdJim Macd Posts: 750

    I can't disagree more, Dave. The earlier you plant out the long the plant has to establish. If you don't plant out you're going to have to re-pot. As long as the plant has room when you plant out it is better than putting it in another pot every time. Obviously not if the plant won't have room. Planting out early means the plant will not be disturbed again.

  • Orchid LadyOrchid Lady Posts: 5,800

    Right, having read all the answers again this is what I am going to do.....

    Leave them in the pots they are in and in another week or so bring them out of the GH. I have an area behind the greenhouse which is paved and quite sheltered from wind and direct sun that they will fit in nicely, I will put them on a pallet cut in half to keep them off the ground and that way I can also put a 'slug pub' between the slats.  I will keep them there and just keep repotting on, removing any flowers and growth tips.

    One last question, will they need overwintering in the GH or will they be ok there until spring?

    Thank you again everyone for your patience.

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