Where do you live? If in southern CA I would say go for it. When I visited the 2007 LA convention I saw the dinner plate size begonia blooms. Not saying you could grow blooms that size without the right bulbs though. Same thing for the 2010 SF convention but I think it was the same grower - hundreds of 7 inch blooms and bigger!

WFF has bulbs that are $50 and up that promise huge exceptional blooms on a tuberous begonia. Too rich for my blood. These are Blackmore and Langdon bulbs from England. They used to have some over $75 for one bulb. Don't see any this year.

I don't mind spending a few dollars on a bulb knowing that by the end of summer it will probably be toast. It served its purpose as an easy flowering annual. I used coir lined baskets for these types of begonias.

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Feb 3, 14 at 19:14

Thank you so much for your comment.

Yes, I also read about the WFF ones. They are the superstars, the branded cultivars, such as Sugar Candy is so marvelous :-) I wish there is a way that we could buy at a slightly cheaper price without the authentication of the brand :-)

From your experience, are those large ones grow in the same way as the normal ones?

Do they flop in wind?

Are they heavy feeders?

Do they need more or less sun, if compared to the normal ones?

Do I need to pinch off most of the buds to ensure the remaining ones to reach the large size?

... ...

This post was edited by jujujojo on Mon, Feb 3, 14 at 19:35

I would direct your attention to a grower in CA who knows the grower of the BIG tuberous begonias. He or they could answer your questions. I rarely grow tuberous due to our long hot (and often dry) summers.

Hopefully you are on FB. Check Mike's site out here with big tuberous begonias. He will probably give you many tips and other people to contact.

https://www.facebook.com/GazeboPlantRental

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Feb 3, 14 at 21:41

I was asking for wider opinions, not just the growers. I guess these are not very widely cultivated?

Here is a picture of a large one:

{{gwi:430134}}

I don't think a lot of folks grow tuberous as much as all the other varieties. Try the Scottish society - they are very big into growing tuberous.

Here is a picture of some of the flowers at the S.F. convention (2010)

they do not do well in hot weather - the best growing places for them are 'cool' summer places - north cali, british columbia, new england, nova scotia, higher elevation cooler areas of north-west and appalachia and such. they like cool nights (60s) and a long growing season before they bloom. so if your summers are hot and/or your summer nights are warm (70s) you'll have a problem - they won't bloom.
they need to be staked or stems can break easily, especially in the wind. also do not pinch them, do not remove the main stem. if you do, it'll reduce the bloom size. if you remove top flowers - they might not even bloom at all.
in general they are quite different from regular hybrid basket begonias like non-stops.

Posted by petrushka z7b (My Page) on Sun, Feb 9, 14 at 18:15

Thank you so much.

That seems to be the script for all tuberous begonias. But I had them for many years (not the giant ones). I had grown them wonderfully in extremely hot summers. I even had the non-stop ones growing in pots and persistently indoors. They bloomed and grew just fine. In my opinion, if you know how to manage light and water, temperature is not an issue. Outdoor summers are always cool enough for these. If you pay close attention, they even grow well completely inside near windows. The only things that I needed to be careful are rain, manures, wrongful watering because they can rot the tuber.

'Outdoor summers are always cool enough for these.' - it all depends where you are.
and certainly not when temps at nite are in the 80s! and day in the 90s.
they grow ..somewhat.., but blooming is a diff matter.
and high humidity becomes a problem - mildew. if it's low humidity and high temps then you get mites.
indoors - that's quite possible with a/c. i had to take my non-stops and tuberous indoors when it was pushing 90F here. and kept them inside until cool off. then back out. but they finally started a good bloom only when night temps lowered to 65F.
just growing leaves does not inspire me much, even though i think that the leaves are beautiful - i want flowers! and not just one or two.
i am certainly curious to see pics of yours if you manage to make them prosper - not many people post about large flowered begonias here. i was asking some questions and got very few replies.

Okay, our local WM carries double Pastel tuberous begonia. I bought one bag of 7 large tubers.

It is claimed that their flower is 15 cm or 6 inch across. It is also claimed that they have more petals. So, I am happy to have these this year.

Right now, the bulbs have not pink shoot. Is there any way to promote them to wake up?

it's too early (depending where you are - which you are not saying). but in any case, mine are actually showing a bud.
i put them in moistened mix in a warm spot (70f) to get them to grow more buds. which they are doing presently.
what i've done for non-stops is i dipped them in warm water for a min or too - then dry them up with a paper towel and put in plastic green grocery enclosed bin with a few holes for ventilation - keep dipping them in warm water ev 4-5 days . in a warm space too - they should show pink grow buds in a week or 2.
then you can put them on a dampened peat and keep them moist/covered until they start showing root nubs - then you can plant them, shallow at first, easy on water. then slowly cover them up with 1-2" of soil mix, as the leaves will be growing - you can give them more water. they are slow in the beginning so have patience.

Posted by petrushka z7b (My Page) on Wed, Feb 26, 14 at 23:06

I also had non-stops before :-) But it seems the flowers tend to be somewhat smaller.

yep. but at least you have multiple flowers with non-stops... my tuberous produced exactly 2 rather weird looking flowers in late aug - and that's in it's 2nd year...it's def not what was on the pic when i bought it either...it looks to be a healthy large plant, but...
i am just going thru the motions to see how long it will survive, no more large flowered purchases here.
i am sticking with non-stops :). though am very envious of large flowered varieties. so post when yours bloom!

Posted by petrushka z7b (My Page) on Thu, Feb 27, 14 at 20:12

Aha, they have shown shoots now. Initially, it is just pink spots, then the spots rise up into buds.

I have a way to do it. Wet a rug and squeeze all the water out. Place the rug at the bottom of a transparent box. Then, place the bulbs on top. The rug must be dry to touch but it keeps the moist well. I can also observe what is going on.

that will work. i use a coir matting piece (like they line the baskets with) instead of damp paper towel. mine non-stops are showing little pink pin-heads now too. i check them daily.

I took a picture of the cover. Are these a type of non-stop tuberous begonias?

{{gwi:430135}}

they could be. non-stop/go-go/solenia are trademarks - so it should be on a box.
they have smallish tubers that are hard to overwinter - so few people do. usually they are grown as annuals from cuttings for sale. and they are much cheaper then large flowered named tuberous varieties.
also they are much more heat tolerant.
it should say smth on the package. look on the back. is there a nursery name? origin? country?

Posted by petrushka z7b (My Page) on Sun, Mar 2, 14 at 19:17

I think these are not. The bulbs are very large - half the size of my palm. They carry no sign of non-stop anywhere on the box.

I'm adding a picture of the bulbs in the bag. I hope it shows the quite large size of the bulbs.

{{gwi:430136}}

that looks large :). so this must be a large flowered kind.
they are quite different from non-stops.
the culture/optimal growing parameters are somewhat different for large flowered varieties. they like it on the cool side.
i stumbled on this post today: may be it'll give you more info on planting the tubers.
however, i came upon some posts that state that california corms should be planted initially differently from english begonias.

Here is a link that might be useful: english begonias

Posted by petrushka z7b (My Page) on Sun, Mar 2, 14 at 23:04

Thank you so much. I look forward for more information. I will also post updates.

I grow a lot of tuberous begonias, though none that are giants. Biggest flower maybe 4â . I have enough problems with the stems breaking off with the weight of the flowers, with the ones I have. I end up supporting that heavy head with a forked stick. Mine are in dappled shade, a few hours of direct sun. Wind wreaks havoc. Mine are from Easy to Grow bulbs, if you want to check them out. I overwinter in my basement.

(Note: I only buy the rose form from them. The fancy picotee kinds have not bloomed true to picture: not even close. Right colors, wrong form (long petals, no ruffling). They donâÂÂt breed them, so it is not their fault. They replaced them, but all the new ones bloomed the same way. I am still looking for a source for those. I bought some from Home Depot yesterday, just two to try, as they were expensive for the small size of the bulb (about 1 ýâ ).

One thing I discovered. Every year I end up buying some baskets of already flowering hanging begonias. Those are most likely grown from cuttings, as described above. When they go dormant, any corm thatâÂÂs forming is too small to find. I bring them in before the first frost, let them die down, stop watering, remove dead stems and leaves, then store the whole basket undisturbed on the floor of my cool basement. In the early spring I bring them up, and they start growing again. In time the corms get bigger and bigger. This has worked very well. They tend to start blooming after the purchased ones, which means I have baskets to fill in after the summerâÂÂs new purchases are winding down.

â¢Posted by petrushka z7b (My Page) on
Sun, Mar 2, 14 at 23:04

â¢Posted by linnea56 z5 IL (My Page) on
Sat, Mar 29, 14 at 15:18

Hi, our low temperature will be -1 C or 30 F. Do I need to move the pots back indoors?

you mean you're sprouting the corms outside in low temps? do they have any leaves yet? below 40F they will suffer even when in full growth in the fall.
normally it's recommended to sprout them in warm place (70f) - if they are cold and damp while there are no roots the tubers can rot very easily.

â¢Posted by petrushka z7b (My Page) on
Tue, Apr 8, 14 at 15:00

The corms have shoots and roots already. I put them outside in dappled shade and they seem to grow well. But the temperature has always been just above freezing. I will move them back indoors then.

Wow, this is very difficult to start.

Out of the seven bulbs, one never showed any shoot. Two had shoots but then the shoots disappeared.

The other four are growing okay at vastly different speed.

Some images:

The left one grows so much faster!

{{gwi:430137}}

{{gwi:430138}}

They are at far right:

The one on the left is only a small shoot at this time.

{{gwi:430139}}

{{gwi:430140}}

{{gwi:430141}}

What is the plastic wrap for? You do this for roses too?

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Jun 23, 14 at 7:22

We have too much rain! The plastic wraps are reusing those from frozen pizza :-)

Okay. I've never seen it used on mature plants before. Is your soil too water retentive?

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Jun 23, 14 at 12:16

I use normal soil bought from WalMart. We have a ton of local rains. Last year, I allowed the rains to fall freely into the pot, and I lost one bulb.

This spring, I lost three allium because I planted them too deep and the rain is falling and falling.

The difficult times are when the plants are small and when the plants are going dormant.

I think the plants love this cover. I can control how much water to use. I have left my Hippieastrum outside with this protective cover. It rained and rained and the bulb is safeï¼ trouble free.

I've never had to cover mine but then I quit growing tuberous too. The only time I have to be concerned for any potted plant is when the drain hole clogs and water stands in the pot. A quick push of a branch through the drain hole usually fixes the problem.

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Jun 23, 14 at 19:19

Do you have squirrels who dig in the pots? This is very effective to stop the digging.

Not only the pot is covered, but the bulbs lay above the soil. I fill the pot with soil and then place the bulbs on top. Then I cover the bulbs with more soil, so the bulbs are in above pot dirt bulges. This way, the bulbs do not rot. BTW, I place a lot of manure in the pot.

This post was edited by jujujojo on Mon, Jun 23, 14 at 19:28

Yes we have squirrels. Often gravel or a large rock will keep them out. Also if the pot is crowded they usually leave it alone. It is the young plants that you need to be smarter than your average squirrel. I often place a very large rock to 1) hold the plant in place and 2) keep the squirrel from digging. I don't think they can budge a big rock and don't want to mess with gravel either. I actually have more damage from my dogs chasing squirrels or digging after chipmunks. GRRR!

Here is B. 'Robert Golden' resting along my fence in the very back.

Posted by hcmcdole z7 (hcmcdole@bellsouth.net) on Mon, Jun 23, 14 at 21:06

Wow, yours is spectacular!

BTW, we have many squirrels because one of our neighbours keep feeding them. We also have many wild cats, also because one of our neighbours keep feeding them.

We feed the squirrels indirectly with the bird feeder - it is a losing battle at times.

Cats are welcome - to keep the squirrel population down.

At least the elephant ears don't seem to be bothered by squirrels or the dogs.

juju, it's best not to use manure in pots, even composted one. and certainly not raw! begonias are very prone to all kinds of fungal issues and you are taking a big chance. use seaweed/fish emulsion instaed, if you want organic fertilizer.
and it is best to start them in small pots and then uppot a couple of times until you reach a 12" pot.
you started yours outdoors way too early. when tubers do not have enough roots they rot easily when temps are below 55f. temperatures ARE of issue. both low and high.
they hold foliage well and even bloom in the 50s, but they need a well developed root system to do that. and also need to be kept on the dry side.
but... when plants are young and tender, roots need higher temps to grow faster - 60s at least.
your plastic covers are a good idea!
the big one looks good - but you need to stake it, or it can break off very easily at the base.
the link below is the most detailed guide to cultivation i've ever found. they are grown for cut-flower competition, so you won't necessarily do the same, but there is a lot of detail that is very useful.

Here is a link that might be useful: british grower diary

Posted by petrushka z7b (My Page) on Wed, Jun 25, 14 at 12:57

Thank you so much. I completely agree with you. That is, I agree with each of your point.

Out of the seven, one never showed any shoots. The other two are my fault. I moved them out too early, and there are too many manure in the pot.

Yes, the plastic cover is a good idea. I can keep the soil relatively dry. This works great for Hippeastrum outdoors. There is no more worrying about heavy rainfall. BTW, the Hippeastrum loves manure in pot.

My only complain is that the flowers are not as doubled as the pictures, again :-)

Next year, I will do much better :-)

i only tried sev times - but mine were never as big or fluffy as on pics. may be the tubers need to get larger or may be long growing season and special culture (fertilizer?) is necessary. apparently north california is where you can grow them with relative ease. also perhaps pacific-NW?
when i fed my soleil (rieger) and also non-stops with orchid fertilizer for blooms schultz npk 19-31-17 they had better more double blooms. also when in the fall: with nights in the 60s and days in the 70s.
they even continued to bloom well when nites dropped in mid 40s days mid 60s.
unfortunately hotter temps seem to single out/deform the blooms.
the british grower site has exact culture spec: temps by weeks, pruning, fertilizing for best largest blooms. he does grow them in the greenhouse though.

Posted by petrushka z7b (My Page) on Thu, Jun 26, 14 at 16:08

I believe the looks of flowers are genetic. I had a fully doubled one last year. The only problem is that her flowers are smallish. The plant grows fully doubled flowers all the time. I will post some pictures from this year soon.

Let's be honest, we humans are shrewd :-) Next year, I may go to buy those already potted tuberous begonia with large double flowers.

Posted by petrushka z7b (My Page) on Thu, Jun 26, 14 at 16:08

My new begonias pastel mix still have not opened any flowers. It has become obvious that squirrels have been biting them. The squirrels eat the flowers. I opened a big bud bit off by squirrels. It does have many petals and they look wonderful. So, the product is good.

These days, our neighbours feed them salted peanuts and bread. So, the squirrels are thirsty. They bite the flowers off. They also bite at the base of the juicy begonia stems.

I now realize that it was not really my fault that all but 2 begonias bought this year failed. I remember they had leaves and appeared to be growing okay, then suddenly, the stems appeared to be scarred at the base and the plants died.

Now, a few days ago, the squires actually bite off a couple stems off the begonia. So, I know what happened. How sad.

Unfortunately, those bulbs with stems bit off did not re-sprout in summer heat. They died.

I will have to buy more next year.

This post was edited by jujujojo on Tue, Jul 15, 14 at 20:01

you'll still have squirrels next year too though.
i read that putting down some moth balls around the pots or sprinkling moth ball flakes (naphthalene) will deter small animals, including squirrels. however if it rains a lot, they'll dissolve fast. so you need to devise some sort of loose cover over moth balls - at least in pots (like under your rain-covers?). they will still smell them and keep away.
it's worth trying.

Squirrels will often bite things they donâÂÂt like to eat. They were biting my tomato fruits regularly, lily flowers, etc.
I have read that if you provide water, they drink the water and leave the plants alone. I have done this, and it works. Not foolproof, but worth the effort. I just put out plant saucers near the ones I need to protect and fill them with water. I have had no damage to tomatoes since doing this. For my buds it can be rabbits too: I donâÂÂt know if they can be drawn away by providing water.

Posted by petrushka z7b (My Page) on Tue, Jul 15, 14 at 14:21

Will try.

Posted by linnea56 z5 IL (My Page) on Tue, Jul 15, 14 at 16:34

I did try placing big bowls of water. The squirrel damage becomes serious. After drinking, they get high and bite more stems and play among the vulnerable begonia branches. This spring, I saw them mating in front of me. They do not feel ashamed, oh my.

Oh my! You didn't tell them to get a room? HA!