Taken from Ken Ames' talk, transcribed in the February 2007 meeting minutes presented in the Plumeria World
Ken stated that he had temps of 24°F degrees for 3 nights. It was a sustained freeze for the entire night. He stated that your plumeria should be fine if the temperatures are into the 20s only for a short period of time, 30 minutes or so. It is the extended period of cold that causes damage. Of the 67 trees that he had planted in the ground, he had to cut back 62 of them to the trunks. 100% of what he had in outdoor pots did not make it.
When the temperature drops below freezing, the latex freezes. Once you decide to cut the plant you need to make sure you cut to white wood. You will also want to seal the end with lime paste or Dap. The lime paste has a natural antifungal element in it.
Ken suggested that one thing that can be done if you know there is going to be a freeze is to hose off your plants, because the dust will attract moisture to the plant and cause it to freeze. Also, if you have an eave s or patio cover, move your plants under them. Even that little bit of protection will help.
Several suggestions were made about some other things that might be done.
- Carl Herzog said that Styrofoam cups can be placed over the tips.
- Someone else suggested using white cotton socks over the tips.
- Old-fashioned (non-LED) Christmas tree lights can be wrapped around the plant for additional heat.
- Nursery supply houses carry a freeze cloth that can be used to cover your plants.
- Do not use plastic to cover your plants because it will retain the cold under and help freeze the plant.
- Damage from freeze will not travel down the plant, but rot damage will. Freeze can come up from the bottom of the plant too. If you have to cut back to the trunk, don’t worry. As long as the roots aren’t dead, the plant will come back.
What to do if you have freeze damage
- Cut now! Take a cut to where you believe the black and gunk end. Then take one more cut to be sure. It is imperative that after each cut you wipe your cutting blade clean with rubbing alcohol. Then seal the end with a pruning sealant like lime paste or DAP.
- Watch the plant closely and if the black continues to move quickly then cut and seal with whatever strong sealant they normally use.
- Make sure the plant is hydrated; when the plant isn't hydrated, the cold damage is worse on a weaker plant.
- Next move the plant closer to the house or a wall where the sunlight has warmed it all day (radiating heat). If the plant can't be moved, cover with frost cloth.
- Do nothing. If some of the dead leaves on plants are unsightly you can cut them but they may also act as a protector for the new tip growth on most plants.