Expert: C.L. Fornari - 5/3/2008

Question
Hi
We are in Wisconsin. Have a greenhouse attached to our home and have experience with it.
I brought home several garden center small potted petunias from Louisiana back in February when Wisconsin had 3 feet of snow. They have been increasingly potten up to be the center plants in 10 hanging baskets.
We've tried to propogate new babies on the outsides of the baskets using a variety of "pinch and poke" techniques - dry poked, with or without rooting hormone, etc. But they are not taking despite careful watering, semi-shade, rotating to available light in the GH etc.
Gee- petunias should be a cake walk..we routinely propogate impatiens, including doubles and new gunieas and fuschias ..but can't seem to get anywhere close to 50% on dumb petunias!
Any suggestions/
Thanks
Steve & Kathy
Hortonville WI

Answer
Steve & Kathy,
You're right - petunias SHOULD be a cake walk!  I propagate cuttings by the following method:  I cut a five or six inch stem, strip all the lower leaves off and coat the entire lower part with rooting powder or gel.  Then I put them in damp seed-starting mix, push in the mix and water. I keep them in a shady part of the GH until they start to recover or grow - if they have been rooted in jumbo six packs I repot, but if I've rooted in 4" pots I leave them and once they start to grow I put them in the sunny areas and pinch them.

My only thought about what you've said is that you've tried to root them "on the outsides of the baskets" - is there time-release fertilizer in the soil?  Is the potting medium in the baskets "barky" - sometimes time-release fertilizer will inhibit rooting and a growing medium with more bark, while good for mature plants, doesn't keep the area around the roots damp enough to stimulate the rooting.  And, thinking out loud here, perhaps the other plants in the basket have a more extensive root system then you imagine and they are taking the water away from the cuttings?  

In any case, if you haven't tried rooting the cuttings in their own pots with fresh soil I would do that.  

I hope this helps!
C.L.

C.L. Fornari
www.gardenlady.com