There is a wealth of information on the container gardening forum. Many of us here, with our rose ghetos (the sorry fate of roses that were bought with no space to put them-yet) also mix up their own potting soil to use.
New dirt vs old dirt: well, it does not hurt to knock out a plant and see how the roots are doing. After several years the pots may become root bound and you may have to saw off a bottom, and a corner or two and replace the soil from the bottom up and sides. I add a slow release pellets with the soil mixture with no problem.
There are no rose police and you can try anything although even Mini roses tend to grow huge with proper care.
After the leaves start cracking then I like to use a weak soluble fertilizer solution.
Peter beales is a big fan of growing roses in pots. Have fun regardless.

Here is a link that might be useful: Not many MG fans here also

That link did not work try this one

Here is a link that might be useful: Al s' mix and other info

Hi!

Thanks so much for the other forum..
I will head right over.

You know, we DO like Miracle Gro potting soil, and their "Garden soil," too.

A study recently done here by the Dept. of Agriculture placed Miracle Gro at the top of the heap for bagged potting soil.

That said, DH usually adds to it "a little of this, and a little of that." But honestly, it's far better than anything else we can buy in our part of Southern California.

Jeri

I don't think it's a good idea to plant 2 roses in one pot because you will end up having the root system tangling and choking each other, therefore making transplant a difficult task later on. Roses tend to grow very quickly and by 2nd year, you will find that a 20cm pot is far too small for your roses unless you prune them. I used to use inorganic fertilisers but I now change it to organic pellets to prevent the build up of salt/white solid particles clinging onto the pot which I believe is not healthy for the rose. I heard that Glamis Castle is a blackspot magnet. So you may need to spray it.

I answered your top dressing the pots question in your other post.

I would NOT put two roses in one pot and certainly not two Austins. They tend to be rather largish shrubs and there would not be enough root room in a single pot, no matter how large, for both roses to thrive. And it would be enormously top heavy as well. Go with two of the largest pots you can find and plant them separately.

You don't need to use any particular brand of potting soil. It just needs to be a good light weight, well draining potting soil. Never use regular garden soil, it's too heavy and won't drain properly. Miracle Gro soil is fine. DA just probably wants to sell you their fertilizer. I've used soils with and without fertilizers in them and there was no difference. These days it's hard to find a potting soil without fertilizer in it. I've also used soils with and without the water crystals and I haven't seen that that made any difference either.

I've posted a link below to a recent thread about growing roses in pots where I and others explain how we've done it.

Here is a link that might be useful: Roses in containers

http://forums2.gardenweb.com/forums/load/roses/msg0118375730759.html

I think (from my reading) that Glamis Castle is like Fair Bianca in NOT being a very vigorous rose. (I gave up on Austin Whites some years ago, tho I still moon over Fair Bianca.)

That said, I think I would avoid two roses in the same container, unless you are talking about a massive, massive container. You said 12 inches. In our experience, a 12-in. container is insufficient for anything greater than a Micro-Miniature. You might get by with a 24-in container, but even that would be tight, if the rose is healthy.

Jeri
(Who has FAR too many roses in containers)

I think that's because you have a much longer growing season than I do, Kathy. I don't have to repot mine for at least 3 years and sometimes as long as 5 because they only grow for 6 or 7 months of the year.

Hi and good morning and thank you SO much for the excellent help!

I am going to get bigger pots. I know Glamis Castle is supposed to stay pretty small but it is already 2' tall in this pot. It's covered in buds. Is it ok to put in another pot now or should I wait until next year?

I am already so addicted to studying! I have read so much.. hours and hours. I can't stop. I am a gonner.

I just ordered 5 more roses from Coolroses.
I got Benjamin Britten, Carding Mill, Disneyland (OMG WOW! what beautiful pix of this rose online!), Alnwick and a Pink Intuition. I have read that Pink Intuition is a pain in the arse.. difficult and moody. I want to try though!

This forum is incredible. I am learning so much. It has helped me release some of my fear of growing roses in FL!

Love you guys.
Cary~

Cool roses sells their roses on Fortuniana rootstock. That's a rootstock that is good for Florida's nematode ridden soil. Another thing about Fortuniana rootstock is that it increases the vigor of some roses and they can grow quite tall on it. It is also known for having a more shallow root system with less cold tolerance. Now the cold tolerance part is not a problem I would think in Florida, but if you have strong winds you might want to think about where you will place your pots before you fill them up with roses. I have grown quite a few roses in containers and in Oklahoma at least, the wind can cause major problems with knocking over even large containers full of roses...As for when you "up pot" a rose, there is no set time like spring. You do it when it needs it. Because you are in a warm climate your roses will grow quickly and you may find out you need to "up the pot size" on them sooner rather then later....Good luck to you...Maryl

You can transplant them into large pots at anytime. Just try to disturb the root ball in the original pot as little as possible when you do it.

Sounds to me like you are good and hooked on roses now!

Here's what I was talking about, about pot sizes.

We have two "Roseville Noisette" plants which have grown up in 1-G pots, and were ready for transplant.

In maturity, they should eventually hit about 3 ft., but they're very fragrant, and I wanted them up higher. So they've just been transplanted into these big, big pots. (We had big fuchsias in those pots for some years, but fuchsia gall mite just devastated them.)

The two little "Rosevilles" should do really well here. THIS much size is probably more than is needed, but not a LOT more, for a full-sized rose.

{{gwi:237896}}

Jeri

Yeah, that's about the size of my big pots too, Jeri. But I don't use ceramic, pottery or terracotta any more. They are just too heavy once planted and they don't winter. I have several of the new foam/resin pots that size and I like them a lot.

I just came in to check this out again and WOW look at that huge pot! I am afraid they are so expensive here that I could not afford (4) of them like I need right now!

I did get 20" plastic pots though.. twice the size of the old ones and am potting my new DA's (Pat Austin, Jude the Obscure and Alnwick) for their first year, in these instead of the smaller 12".

Three 1 year old potted ones from last year are going in the ground soon too. I appreciate all of you so much and I am rightly and surely hooked now! This AM my husband and I were talking garden design and we are going to work on a future design soon.

Big Lots has reasonably priced large plastic pots.

Most places, you're likely better off with plastic of some sort.

Those big ones tho -- LOOK AT THAT GLAZE!
They came from Costco -- imported from VietNam -- They've never had them this big again. They were sure a bargain.

Normally, though, we use plastic, even in our mild SoCal climate.

Jeri

AND, if you're gardening in Florida, I think we'd all recommend our good friend Sherry's blog: If Sweat Were Irrigation

Here is a link that might be useful: If Sweat Were Irrigation