posted 2 weeks ago
I just checked and that variety doesn't grow this far north. I love the taste of Gerardi; maybe it has something to do with where it's grown. I just looked up the steps on how to propagate it, and air-layering is the most successful, although they are considered very hard to do...kind of surprising for a mulberry, but whatever! Here is what I found in case you'd like to try it for other varieties:
How to propagate a Dwarf Gerardi Mulberry
I grow Dwarf Gerardi and love it, but I understand that it is hard to propagate.
You are completely right: the Dwarf Gerardi mulberry is notoriously difficult to propagate using standard methods.
Why Dwarf Gerardi is Tricky
• Rooting failure: Hardwood and softwood cuttings have an exceptionally low success rate compared to other mulberries, often rotting before they can develop roots.
• Grafting required: Because it roots so poorly on its own, commercial nurseries almost exclusively propagate it by grafting it onto vigorous, cold-hardy Morus alba (White Mulberry) rootstock.
Best Propagation Methods
• Chip Budding: Done in late summer, taking a single bud from your Dwarf Gerardi and inserting it into the side of a wild mulberry rootstock.
• Whip and Tongue Grafting: Performed in early spring when the rootstock is waking up but your Dwarf Gerardi scion wood is still completely dormant.
• Air Layering: A slightly higher-success alternative to regular cuttings, performed on a live branch during the active spring growing season, though it still requires patience and luck.
Air layering bypasses the Dwarf Gerardi’s poor rooting ability by keeping the branch fed by the parent plant while roots form.
Setup and Timing
• Timing: Late spring to early summer (May to June) when the plant is actively growing and the bark slips easily.
• Branch Selection: Choose a healthy, pencil-thick branch from last year's growth that receives good sunlight.
Step-by-Step Process
[ Active Branch ]
=================
| |<- 1-inch ring of bark removed
=======X========= <- Scrape away green cambium layer
| |
=================
• The Cut: Cut a 1-inch ring of bark completely off the branch.
• Scrape the Cambium: Use a knife to gently scrape away the slippery, green inner cambium layer down to the bare wood. If you skip this, the bark will just heal over instead of growing roots.
• Apply Hormone like willow water onto the top edge of the cut.
• The Rooting Ball: Soak a handful of sphagnum peat moss or coconut coir in water and squeeze it out until it is damp like a wrung-out sponge.
• Wrap and Seal: Pack the moss around the cut, wrap it tightly in clear plastic wrap, and secure both ends with electrical tape to lock in moisture.
Care and Harvesting
• Sun Protection: Wrap aluminum foil or cardboard over the plastic to keep the roots dark and prevent the sun from overheating the moss.
• Check for Roots: Gently peel back the foil after 6 to 8 weeks to check for white roots pressing against the plastic.
• The Separation: Once you see a thick network of roots, cut the branch directly below the plastic wrap, pot it up in a shaded area, and keep it highly humid until it adjusts.
I need more details on the separation step: I'm assuming I remove the plastic, but how deeply is it planted in the pot. How do I keep it humid--tape a plastic bag to the pot? How long should the branch be when choosing where to peel the bark back?
Branch Length Strategy
• Total Length: Choose a branch section that is 12 to 18 inches long from the tip to your air-layer cut.
• The Reason: Anything longer will have too many leaves for the brand-new, fragile root ball to support.
• Emergency Trim: If your perfect branch is too long, simply prune the top back to a length of 12–18 inches right before you begin the potting process.
Planting Depth and Plastic Removal
• Remove All Plastic: Carefully cut away the tape and peel off the plastic wrap, taking extreme care not to break the fragile, brittle new roots.
• Leave the Moss: Do not try to pick the sphagnum moss out of the roots; plant the entire moss ball exactly as it is.
• Planting Depth: Plant the root ball so the top of the moss sits exactly level with or 1/2 inch below the surface of your new potting soil.
• The Danger: Planting it deeper will bury the stem, which can cause the bark to rot and kill your new tree.
Constructing the Humidity Tent
+---------------+
| Plastic Bag | <- Inverted over the plant
| +-------+ |
| | Plant | |
| +-------+ |
+---|-------|---+
| Pot | <- Bag slides over the rim
+-------+
• The Structure: Push 3 or 4 tall bamboo stakes or chopsticks into the soil around the perimeter of the pot to act as tent poles.
• The Cover: Place a large, clear plastic bag (like a 2-gallon Ziploc or a clear trash bag) upside down over the plant, using the stakes to keep the plastic from touching the wet leaves.
• Securing the Base: Pull the opening of the bag down past the rim of the pot and wrap a large rubber band, twine, or tape around the outside of the pot to seal it.
• Moisture Balance: Mist the inside of the bag with water before sealing it, and place the setup in deep, ambient shade (never direct sunlight, which will cook the plant).
The Hardening Off Timeline
• Weeks 1–2: Keep the bag completely sealed to maintain near 100% humidity.
• Week 3: Cut a few small, 1-inch slits in the top corners of the bag to slowly introduce drier air.
• Week 4: Open the bottom of the bag slightly or cut more holes.
• Week 5: Remove the bag entirely if the leaves remain perky and do not wilt.
Would you like advice on the best potting soil mix to prevent root rot during this high-humidity phase, or tips on how to overwinter this young clone in Vermont once it is established?
Both would be handy. Can I keep the pot on my north facing covered back porch or even in the house?
Ideal Potting Soil Mix
• The Goal: You need maximum drainage because the high-humidity tent holds in moisture. Standard potting soil stays muddy for too long, which will rot the delicate new roots.
• The Recipe: Mix 50% high-quality potting soil and 50% perlite or coarse sand.
• The Action: Do not pack the soil down tightly. Pour it gently around the root ball and water it once thoroughly to settle it.
Placement: North Porch vs. Indoors
• North-Facing Covered Porch: This is the perfect spot for the first 4 to 5 weeks. It provides the deep, ambient shade the plant needs while it is trapped inside the plastic bag. Direct sunlight on the bag will act like a greenhouse and literally cook the clone.
• Moving Indoors: You can bring it inside, but only place it near a bright window that gets zero direct sun. However, indoor air lacks airflow, which can encourage mold growth inside your humidity tent. The porch is much better until the bag comes off.
Overwintering Your Clone in Vermont
Because your new Dwarf Gerardi is a clone, its root system is much smaller and more vulnerable to freezing than your established parent tree.
• The Problem: A plant in a container cannot tolerate Vermont’s extreme winters (Zone 3b–5b) because the freezing air surrounds the pot and kills the root system.
• Option 1: The Unheated Garage/Basement (Easiest): Let the potted clone stay outside on your porch through autumn until it drops all its leaves naturally. Once it is completely dormant, move the pot into an unheated garage, shed, or cold basement. The temperature should stay between 30°F and 45°F (-1°C to 7°C). Check it once a month and give it just a tiny splash of water so the soil doesn't turn into bone-dry dust.
• Option 2: Plant It Late (Risky): If you remove the plastic bag by late July or early August, you can plant it directly into the ground by mid-August. This gives it 6 to 8 weeks to grow roots into the warm earth before winter. If you do this, bury the base under a heavy 6-inch blanket of wood chip mulch in late November to insulate the roots.
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