Not enough to worry about :-) Yes, it could elongate some but very little compared to the grafted portion.

The most important pruning of container grown plants will be root pruning. If you intend to keep these trees in a container on a more or less permanent basis, they will require routine repotting with fresh potting soil and regular root pruning.

Gardengal, can you explain what you meant in that first sentence?

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Container_blueberry, the rootstock of your plant will grow larger around but will not grow taller (unless it develops a root sucker that's allowed to grow). The graft union (where the rootstock and scion meet) will be at the same level decades from now as it is right now (unless you replant the tree at a different level). Woody plants grow from their tips, not by stretching. If you drive a nail in a tree 4.0' from the ground and leave it there for many years, the nail will still be 4.0' from the ground. The tree will grow around it, but its height will not change.

Gardengal,

Why do you mention root pruning? Is this to control the rate of top side growth so I don't end up with a very stocky tree after pruning off branches?

Thanks

Rootstock does not grow upward. If you keep in a container forever, you'll need to root prune as the size of the plant will be too much for the container. You'll be doing maintenance every several years on the soil anyway, so that is the time to root prune.

Dan

Container_blueberry, if you don't already have a good handle on what soil mix to use, be sure to read Al's thread in the Container Gardening Forum about container soils, drainage, aeration, durability, etc.

Here is a link that might be useful: Container Soils - Water Movement & Retention

i will posit some issues that come to mind ... that i seek answers for ...

repeated root pruning is a form of bonsai, isnt it ...

and it will help maintain a smaller plant overall ...

but wouldnt it bonsai fruit size????

or can that be overcome with proper fertilization???

next .... most food production trees need to achieve some level of maturity .... which is a function of a root mass sufficient to enable flowering and fruit ... again.. if you have to keep cutting the roots ... wont you delay proper root mass for maturity????

there...

now... blueB .... it is commonly said.. right or wrong.. that a tree is at least twice as big below ground as above .... so what gal and the others are wondering about.. is how you are going to get a tree to produce fruit ... when you are restricting its root mass in what might be called a comparatively small pot ... if you mail order a 4 foot tree ... i doubt you are thinking about an 8 foot pot.. to provide a mind picture of what i am suggesting ....

i see no reason blueberries cant grow in a pot .... but it might be a leap of faith .. to think you can successfully do the same with a tree that you want to make fruit ...

that is not to say dont try or that it cant be done ... its just a matter of maintaining YOUR EXPECTATIONS of success .... in other words.. IMHO.. it is not going to be easy ....

in my experience.. successful fruit production is very hard in mother earth ... adding all the variables of dealing with pots.. seems severely overwhelming to me ....

but the bottom line.. as always.. DO WHATEVER PLEASES YOU..

good luck

ken

ps: there is a fruit forum.. which i havent been to in a long time.. and there was one heck of a pro over there.. that knew.. everything for every fruit .... you might want to try over there also ...

OK Brandon - here is my explanation :-) I wrote that response last night sipping my glass of wine while waiting for dinner to cook. Seems to me that over the years I had seen some rootstocks increase in length (IOW, the graft appears higher than it did initially) but maybe that was just a perception of the increased diameter or the soil level declining. This morning, after I think about and have sufficient caffeine, it doesn't seem very logical at all. I take it back :-))

Ken, I think you need to get out more :-)) All sorts of fruit trees can be grown in containers and it is an excellent way of growing tender or semi-tropical fruits in colder climates due to portability. And essential to those who garden in limited spaces like rooftops or apartment balconies. It helps if it is a naturally small tree or on dwarfing root stock but even that is not essential. And root pruning does not affect fruit size, just as growing on dwarfing root stock does not result in dwarf fruit - if all other cultural conditions are met, the fruit will be of normal size, regardless of the size of the tree or any necessary root pruning.

container blueberry, root pruning is necessary for any woody plant confined to a container. Obviously the root run of a tree in the ground is far larger than a container will provide. Container grown plants will become rootbound eventually and rootbound plants are unable to get adequate moisture, access nutrients and lose vigor and decline. Root pruning restricts the growth of roots to fit the container and regenerates feeder roots that die off quickly when limited by the container size, heat, insufficient nutrients and dry soils. Unless you have a very large container, this type of growing is a natural dwarfing or stunting process, similar to bonsai. Top pruning may also be required but proper root pruning is essential.

I am also thinking about planting a sunshine blue blueberry (semi-dwarf variety that tolerates higher ph) as well as a heritage raspberry and arapaho blackberry in the same container with the tree.

Does anyone see any problems with this approach? Can I plant my Santa Rosa plum slightly below grade to allow more room up top of the shallow rooted berry bushes/brambles?

P.S. My Santa Rosa Plum is very small at the moment (4'-5' tall). The sunshine blue is about 18 inches tall, but compact and very bushy. The brambles were small bare-roots I just bought. The container is 20" wide and displaces a true volume of 12 gallons.

Does anyone see any problems with this approach?

If you have smaller than a 3' x 3' container, all kinds of problems.

Can I plant my Santa Rosa plum slightly below grade to allow more room up top of the shallow rooted berry bushes/brambles?

No.

Most woody plants suffer when planted below grade.

Dan

Gotta go with Dan on this - all these plants will grow :-) A Sunshine blueberry in a container at work is about 4' tall and half again as wide. A 20" container is even too small for the plum. If you add additional plants, they will compete for root space, water and nutrients and none will thrive. And what a headache when it does come time to repot and root prune!

Unless you are doing temporary ornamental plantings, I'd suggest you limit your selection to a single type of plant per pot (especially with berries like raspberries or blackberries - these are caning shrubs). And when choosing container size, plan ahead for growth to limit how many times you will need to pot up.

Grew a couple of Sunshine Blue-berries in 3 gallon pots last year. They seemed ok. The plan is to put them into 15 gal containers this year. The 12 gal container sounds ok for one blue-berry bush but for 3 other plants and one of them a tree sounds like too much for one pot.

Thanks for the replies.

I think I will just try the strawberries. As the tree grows larger I will re-pot with no other plants.