Plants bought in 9cm pots-pot on or plant out?

Hi all,

When you buy plants in 9cm pots, is it usually the expectation that these need potting on or to grow more in these pots before planting out? Does it depend on the plant? They're obviously cheaper to buy than 1-2L potted plants, is that the only advantage? And are there many cons? I.e. in your experience do you just take the hit and just buy bigger or happy to wait for them to grow and save a bit of money?

I've just bought some crocosmia and agapanthus in 9cm pots and I imagine they will not flower this year as they're small (3-6 leaves, 20cm tall). I don't mind that but that is one down side I suppose. I'm wondering whether to plant them straight in the border or keep them in pots for a while. We are seeing a lot of slugs/snails at the moment in all this wet weather is one thing in my mind..

Thanks for the help

 

Hi @Mattyp ,
I pot everything on until they are established enough to handle the army of slugs and snails.

Also, if buying during a less-than ideal weather conditions, it's easier to move pots to shelter if needed. Most plants are commercially grown in greenhouses so need to get used to rain, wind and the hypothetical ray of sunshine

Having said that, container plants can usually go into their permanent containers as they are.

I buy all my plants cheap and small, and have a healthy slug population so that's the only thing working for me.

 

Personally I think the crocosmia would be fine planted straight outside, but not too sure about the agapanthus as l used to grow them in pots in my own garden.

Nine times out of ten I buy plants in 9cm plants and grow them on myself. If you're trying to fill a large area and have patience that is the best way to do it imo.
Also, depending on what you're growing, once they fill say a 1 litre pot, you can divide things such as Heleniums and hardy geraniums (Cranesbills) and pot them up. Alternatively you can by a 1 or 2 litre pot at the garden centre,divide them up and pot them into smaller pots to grow on.
I always have a look at the reduced section to see if I can get any bargains .

 

Agapanthus can take a few yrs to flower from a 9 cm size. That said, I would keep them in pots as they like congested roots.

Crocosmia are very tough and a small one would probably be fine planted out.

In my experience, slugs and snails do not eat either agapanthus or crocosmia!

I buy small as it is better value and I like watching things develop.

 

Hi all,

Thanks for the comments, looks like I'm adopting this lot for a bit then, hmm I was hoping to plant them out and put my feet up .

I did think the croc was the safer/more reliable buy to be honest from what I've read about agapanthus, especially those planted in borders can be tricky. Can only try and see.

Obviously these are quite tall plants even now they look a little ungainly in the tiny pots. Maybe what I'll do is put the crocs in one large ish container and the agap's in another and keep them there for the summer and perhaps put them in the border in autumn? Or would I then be best to wait until early spring next year to move them to ground? Both I think are deciduous, I suspect spring is the answer.

I think for both they can be planted quite tight together. RHS said 8cm spread for crocosmia which seems very tight to me. These agapanthus I think it said 40cm spread but I saw monty Don plant 3 from 1l pots I think into one container and they looked very tight but if that's what they like.

 

I won't put them in pots a lot bigger straight away. Gradually working up the sizes is best. Agapanthus have extremely tough roots. I wait till the pressure is starting to make the pot (I use plastic ones) misshapen and then I usually have to cut it off. To divide the root ball, you might need a saw. They like a lot of moisture in summer, but to be dryish through winter, so I have the pots under an overhanging porch then.

Crocosmia are really lots of plants together. Each corn throws up a green leaf with flower. Gradually the corns bulk up and grow offsets, which throw up their own greenery. I don't think they can really be too close as they just spread outwards. Some are more invasive than others. They are pretty tenacious.

 

I agree - Crocosmia can be planted out just now. They'll be fine, although we do get them eaten by slugs here. They usually manage to come through though.
I don't grow Agapanthus any more, but I'd grow those on.
It always depends on the plant itself, and time of year, so a plant filling a 3 inch/9cm pot will be fine planted out at this time of year and through summer, if it's something tough. Earlier in the year, and not properly filling that size of pot, and it's always safer to grow them on.
Anything not as tough as things like Crocosmia or hardy geraniums etc, or slower growing, will always be better grown on until the following year.

 

It's strange - I always subscribed to the view that agapanthus needs to be pot bound. But I have a couple in the garden that are quite happy and floriferous. Maybe it says something bad about my soil!
Not all crocosmia are very vigorous, so if your slugs are particularly greedy like mine, I'd keep in bigger pots for a while. My slugs have even been eating digitalis flowers, which never used to get touched!

 

Thank you all, some good feedback there, I appreciate it. I think I'm going to risk putting the crocosmia straight out. I'm having to be quite vigilant regarding mollusks anyway for other plants, hostas/brunnera. The agapanthus I will grow up until at least next spring. Looks like I need to go buy some John innes 2/3 to put the agapanthus in so says RHS. Any direct experience as to whether MP potting compost will suffice?

 

MP is absolutely fine, in my experience. Mine have always lived in that and I get loads of flowers reliably. I feed mine with some slow-release pellets in spring. You can feed after flowering as next yr's flowers start to "set" then, but spring, just as it is sprouting, works for me. Mine are 24 yrs old now and going strong! The original has been divided a couple of times and all the divisions are now in pots about 10" across and 12" deep. Lots of sun in summer plus winter dryness seems to be the key.

 

And of course worth adding that any plant you can buy as a bulb, bare root or a corm it makes sense to buy them in that dormant form instead of 9cm pots as you're paying for the compost and care that you can put on yourself.

 

But ... buying them with leaves at least means you know they are not dead!

 

I do agree with most of what has been said already but personally for fairly vigorous perennial plants I have found they do much better in the ground earlier. I say this for several reasons, with the main one being my forgetfulness at watering them but moisture conditions tend to be more stable in the ground. The other reasons are it gives the roots a chance to stretch and establish, not run rings around the pot. It will depend on how good your soil is as to whether it works for you and the particular species but for me seed sown plants that I've grown on in pots tend to be far far smaller than those planted out earlier.
A major issue with small plants is competition but if they are given enough space and light they can thrive and grow quickly although again it really depends on the species. I would happily plant smaller 9cm specimens of some species that are not normally predated on by molluscs because I don't see a real benefit to growing them on.

 

All good points thank you. From my own limited experience this year. Slugs have been the main issue with putting plants straight in the ground. But I was nieve and hadn't protected them. But it's likely everything I put in happened to be on the favoured dinner menu. Or they see these plants as stressed as they haven't settled and head for them. I moved a magnolia from a container as it wasnt doing well there to the border thinking it would be happier but I forgot to check it and the slugs have eaten all the leaves so suspect it's done for. But I think your points were numerous and valid if we take pests out of the equation

 

Everything seems to be on the "favoured dinner menu" this yr. I suspect there has been such a population explosion, they are turning to things they would not normally touch. Plus, plants battered by wind and endless rain may be less able to repel an invasion of munchers.