BIG hibiscus

[Darkhorse]

Hi Charlie and all,

So I've been growing hibiscus for two and a half years now, and I have several older plants that are starting to get pretty large.  I'm interested in what pot sizes you guys with larger plants max out at?  What pot size is most practical for someone wanting a BIIIIIG plant (Bart you've set the bar with your 7' Island Queen), but doesn't consist of 1,000 lbs. of terra cotta?    I think I remember reading that HVH's stock plants stay in 5 gallon pots.  Inchwise, how big is a 5 gal. pot?  Around 20"?  I imagine I could move the big ones with a large hand truck or garden cart but don't want to get to the point where this isn't possible. 

Also, does plant management in general change when they get so big?  I'd like to have a greenhouse by next winter, but want my plants to fit!  I can only imagine how many spider mites could live on a 10' hibiscus..........................

[Doll]

I think most 5 gallon pots are around 12" in diameter and 10" deep.

[Charlie]

Good questions. Doll is right, what are sold as 5 gallon pots can vary but often are 10" wide x 12" deep or the opposite 12" wide x 10" deep. I've kept stock plants in many sizes up to 15 gallon pots. As far as plant growth the bigger the better is what we've seen. But, there are often other factors that argue for a smaller size pot such as being able to move them or ship them. I can't even sell off extra 15 gallon hibiscus because few people show up at Open Houses with a vehicle large enough to take them away! Pick-ups will do it but not many enclosed vehicles.

Jordan, in your situation you don't have to decide final size now because you would not want to transplant 6 inch pots or even 2 gallon pots up to 15 gallon. Probably the largest you would want to go this year is 5 gallon pots.The conventional wisdom I heard when first growing hibiscus was that 10" pots are the smallest that will sustain a hibiscus long term. Since then I've found that to only be partly true and have kept hibiscus in plants as small as 4 inch for years at a time. In any case, just a small pot size increase will keep the plants growing ever larger and you can decide as you go just how big you want the final pot size to be.

The other aspect that is very important to keep in mind is that hibiscus need to have actively growing root systems to stay at their best. This can come from transplanting to larger pot sizes or it can come from pruning the roots every other year and then repotting in the same pot using fresh potting mix. If I do not do one or the other my hibiscus languish - they stop growing and bloom less often and eventually lose leaves that they do not replace. Another year or two and they die. But, if roots and tops are pruned as needed and new potting soil introduced every couple of years the plants can flourish for 10 years and up. I have some potted in 15 gallons that are 16 years old now and doing fine.

Charlie

[blupit007]

charlie, i have a question... a bit off the subject.  when transplanting, do you do it when the soil is a bit dry, or wet?  i would think if it were dry, the soil would stay all together better, and if wet it would fall apart and you would loose a lot of it...  i always was curious about that.

[Darkhorse]

Charlie, thanks for the good info.  I'm really looking forward to this year; partly due to the fact that some of my plants are larger now and very full, and partly because I seem to spend the first year or two with them doing a great deal of pinching and pruning.  I like a nice, full bush and thus don't get to enjoy as many flowers as I'd like.  Now that some are larger and the bushes are taking shape, I can sit back and watch. 

This is also why I like to buy in the 4" pot size.  I can shape them from the beginning.

Kristen, I personally find it easier to pot up when the mix is mostly dry.  It seems to help the root ball intact to not have all the extra water weight dragging it down.  I do turn the pots over and try to let gravity do most of the work, but I have still broken roots when soil is wet.  Not sure what the general consensus is on this, though.

[blupit007]

Jordan, that is what I was thinking too. 

[Charlie]

Hmmmm, we never transplant into totally dry potting mix. The mix should be moist enough so that if you take a handful and squeeze it pretty hard a few drops will come out and fall from your hand. But, you are talking mostly about how wet the potting mix that the plant is already in is, right? Ideally it will match the soil it is going into, lightly moist but not sopping wet. I always water again the day after transplanting because you do not want the pots to dry out too much at that delicate stage. You can also water right after transplanting if in doubt.

Definitely if the soil is so wet that the root ball falls apart or the soil so heavy with water that its weight can break roots off - that is too wet. OTOH, you shouldn't be transplanting if the root development is not sufficient to hold the root ball together pretty well. It doesn't need to be rootbound or have roots circling the pot several times but there should be plenty of roots to hold the ball together before transplanting to a bigger pot.

Charlie

[Charlie]

Jordan, it's good to hear that your hibiscus are filling out as they mature. It can take some time and effort to bring a hibiscus to maturity but once you have one for several years they become easier and more resistant to stress. Of course the darn mites have to be kept off, particularly indoors. I had a small outbreak a couple of weeks ago on the plants in our office that I use to hybridize with so I increased the Kontos dose to 1/4 teaspoon per gallon and it quickly stopped the problem. I was glad to prove that an increase is effective, at least in these conditions where there is a lot of sun and day temperatures get quite warm so the plants take up the water and whatever is in it.

It should be a good bloom summer for you this year. I look forward to some photos!

Charlie

[blupit007]

I had a small outbreak a couple of weeks ago on the plants in our office that I use to hybridize with so I increased the Kontos dose to 1/4 teaspoon per gallon and it quickly stopped the problem. I was glad to prove that an increase is effective, at least in these conditions where there is a lot of sun and day temperatures get quite warm so the plants take up the water and whatever is in it.

Charlie

Charlie, this also worked for me and my Cindy's Heart!  Although I prolly killed the good mites too!   Oh well, better no mites at all!

[Darkhorse]

Yep, that has been my experience too.  1/4 tsp is sometimes necessary indoors.  I see lots of little dead mites on the bottom of the leaves now.  There are still some adults alive.  I've been squishing them with my thumb.  lol

[Nievesgirl]

Jordan my max is 12 inch pots I will do for my hibiscus. I need two transplant 2 of them soon.

As of transplanting plants. I transplant plant when their soild is on the dry side ( you can pick up the stalk of plant and all dirt comes out with it) Before I do that I wet the new soil and get it pretty moist making sure there is no dry spots. Then I put some of the new miz on the bottom of the pot ( depends how big pot and if its needed) after that I place the plant in the middle and then surround it with the new soil and place some on top of the old. Then I water the plant and see where soil is I usually add more so I can have a nice compact soil. I find this much easier and less stress for the plants.

[blupit007]

Thanks Kerry, that is what I always did in the past with my other houseplants.  I just wanted to make sure that is the correct way, now that I really care about my plants.

[Louis]

and if i may add something. i have found about an inch of worm castings to top the plant off, does wonders.

worm poo got rid of my gnats, i was infested with them a couple of months ago and after i topped with worm poo, they disappeared. its my understanding that the castings are death to many bugs.

louis

[Charlie]

Lou, I think the castings help but are not enough by themselves. I'd like to see some university focus on this issue and determine how valid castings are as a repellant to pests. You know, get to the important stuff, you guys in academia!

Charlie