I have a 5 ft. deciduous frangipani growing in a container which I put outside in the summer and bring in for the winter. The frangipani has scale which I am treating with a spray of 1 cup alcohol to 3 cups of water. This doesn’t seem to be helping.
If I cut it off completely, will it grow back?
Can I take cuttings?
What do you suggest?
I was told not to water my frangipani in the winter. Is this correct?
Also, how do I deal with mealybugs on my orchids?
Frangipani (Plumeria sp.) grow well in containers and respond well to pruning so their size can be controlled. Moving them outside during the summer, as you’ve been doing, can help control scale by exposing them to predators that feed on them. To control scale at this point, I don’t suggest cutting the plant back entirely but you can cut out any badly infested branches. Frangipani will benefit from a pruning of about 20% of it’s branches every other year. Keep in mind, as you are pruning, that it blooms only at the end of branches that are at least two years old.
Scale insects have a simple life cycle of egg, nymph (crawler), and adult. Indoors, eggs can be laid any time under the protective shell. The crawlers will look like tiny yellowish spots. Scale can be controlled by rubbing the infested areas gently with a soft toothbrush or picking them off by hand. If the infestation is large, you may need to spray the plant with a horticultural oil spray, which you’ll find at most good nurseries. Follow the instructions on the bottle carefully and you may need to repeat the treatment several times. It usually takes a month to six weeks to see any significant improvement. In particular, you’ll want to treat the tiny crawlers as it’s at this stage that scale is easiest to control. Spraying, as you have been doing, with a dilute alcohol solution is likely not effective at destroying the eggs.
Winter is the best time to propagate by cuttings once the plant is dormant. Make your cuttings 30-60 centimetres in length. If you see white sap on the cutting end, leave it exposed to the air for a day or two to dry up before planting it in a free draining compost or in sand. Water well and then again every few weeks if the soil is dry. Otherwise, leave alone till new leaves appear. When the leaves appear, replant into a pot with good quality, free draining potting mix.
Frangipani grown in the ground should not be watered but container grown plants may need some water over the winter. Check every few weeks and add a small amount of water if the soil feels completely dry.
The commercial web site, All Things Frangipani, has good information on caring for and propagating frangipani as well as lots of interesting frangipani facts and history, see link below.
The insect infestation on your orchid can also be treated by gently brushing off the mealybugs and if this isn’t clearing up the problem, then use the horticultural oil spray on this plant too.