Q: I am interested in refining my air layering skills. I have watched online videos, and I have had very good success with citrus trees. However, I am having great difficulty air layering Japanese maple trees and non-fruit-bearing weeping mulberry trees. Why am I not having success with these when I use the same techniques as I do with the citrus trees? Barry Gilbert, email
A: Air layering is a method of propagating woody plants by encouraging roots to form on small limbs while attached to the main plant. This is done by wrapping the limb with damp moss and plastic to keep it wet for three months. Once roots have formed, the rooted limb can be clipped off and planted. While I’m not an air layering expert, I do have some thoughts on why your attempts to root Japanese maple and mulberry might fail.
1. Failure to control moisture in your rooting medium. If it gets too wet or too dry, even for a couple of days, the roots suffer. Check the top of the plastic wrap to be sure rainwater is not coming down the stem and going into the rooting space. I use black electrician’s tape to seal the edge of the plastic to the bark. You should be the only source of moisture inside the plastic wrap. A hypodermic needle can be used to add water if it seems too dry.
2. Failure to control temperatures inside the rooting area. Be sure the plastic is shaded if it might be in full sunshine at any time of the day. It will heat up quickly if sunlight passes through the plastic. Aluminum foil works well but you could also slide a plastic cup down over the area.
3. Failure to do the rooting at the right time of year. Trees differ greatly in the best time to air layer. Spring is usually the best time, but early autumn is another good time to try.
4. Failure to try different equipment. Look online for air rooting balls and air rooting cups. One DIY method is to use a small resealable plastic container and lid, with notches carved on opposite sides, to allow the rooting limb through.
Those are a lot of things to try. Let me know what works.
Q: Should I protect my potted yucca for winter? Charlyn Elliott, Suwanee
A: Assuming you have a common Yucca filamentosa, you don’t need to do anything special. It is usually winter-hardy but you can wrap the pot with insulation if it gets really cold. Water it occasionally so the roots don’t dry out.
Email Walter at georgiagardener@yahoo.com. Listen to his occasional garden comments on “Green and Growing with Ashley Frasca” Saturday mornings on 95.5 WSB. Visit his website, www.walterreeves.com, or join his Facebook page at bit.ly/georgiagardener for his latest tips.
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