propogating holly plant
After many attempts to start a holly plant by cuttings, that until today have died and withered, I have spotted one little leaf appearing on a cutting which is inside the plastic bag. Do I remove the bag or what?
Jo Daviess County Illinois
Congratulations -- if you're seeing a new leaf begin to sprout, that's a good sign that your holly cutting is on its way to a working root system!
Now is when your cutting enters the delicate phase of "hardening", that is, transitioning from the moist, protected environment of the propagation chamber (a.k.a. the plastic bag, in this case!) and the real world. The purpose of the chamber is to keep the cutting in a high-humidity environment because without sufficient roots, it can't take up enough moisture for its existing leaves and structure. On the other hand, if its world remains too moist as it begins to function on its own, that's an opportunity for disease (especially fungi) to take hold.
So rather than simply ripping off the plastic bag, you should first loosen whatever's sealing the bag against the air so the cutting can get a balance of some moisture-holding protection, but also some fresh air. If you've sealed the bag at the top, take away the rubber band or tape or string, and allow the youngster to stay in the bag and spend a few days gradually opening the bag in widening increments. If sealed at the bottom, use a couple of clean sticks as a frame (if there's not already a frame holding the bag away from the plant) and loosen (roll up if need be) the bag to allow some air into the chamber.
It's important to gradually harden the roots, too, if the potting medium has stayed quite moist. Don't let the potting medium dry out quickly once you let the air in. Hollies can be prone to root rots and do need good drainage -- so don't soak it, either! -- but do be sure the new and delicate, moisture-acclimated roots don't get suddenly parched.
Do this transition across a few days to a week and observe your cutting carefully for signs of distress. Once the bag is off and the plant is fully acclimated, you should see continuing signs of growth. At that point you can consider relocating or transplanting the new plant.
The University of Missouri extension has a good article on "Home Propagation of Garden and Landscape Plants" that devotes attention to after-care once cuttings are rooted: