homepage logo

Garden Help Desk: Handle poinsettias with care to avoid white sap spots

By USU Extension - Special to the Daily Herald | Dec 9, 2023
1 / 2
Poinsettias are somewhat brittle and it's not unusual for the leaves to leak a little bit of white sap if they're damaged.
2 / 2
Concord grapes are a popular variety in our area. But just like all grape varieties, they need to be pruned while they are fully dormant.

My poinsettia had a few spots of white sap on one of the red leaves. When I wiped off the sap, it just made the leaf look worse. How can I fix this if it happens again?

You’re almost certain to see this happen again. Poinsettias are naturally a bit brittle. The vascular system in the leaves can develop small leaks when the leaves are disturbed, and the white latex sap is very noticeable on the dark green or red leaves. If you’ll place your poinsettia where it won’t get jostled or brushed against, you’ll see fewer of these little white spots.

There is a simple trick to dealing with these little latex leaks: hands off! Just don’t touch that sap. It will eventually dry down into a less conspicuous speck that you can either ignore or brush loose. If you can easily brush off or pick loose the dry latex, that’s you’re cue to ignore it so that a new bead of latex sap doesn’t erupt from that spot. If the dry latex doesn’t brush off easily, wait a few more days and then try again if the sap is still noticeable.

You can also try blotting or lifting off a bead of fresh latex sap with the corner of a tissue. Whichever technique you try, don’t try to wipe it away! As you’ve discovered, that can leave the leaf looking worse.

Some people are sensitive to the latex sap, but poinsettias aren’t poisonous. If you know you are sensitive to latex or have had skin irritation from other plants, wear gloves when you handle your poinsettia.

I was wondering if I could prune my concord grapes now. I have approximately an acre of them and need something to do. Is it too early? Will it hurt them?

It’s too early to start pruning grapes. Grapevines need to be fully dormant before pruning and grapevines in our area haven’t nearly reached that stage yet. Use these winter months to clean and sharpen your pruning tools and make any needed repairs or upgrades on your vines’ trellising so everything else is ready for the new season next spring.

Early spring is the best time to prune grapes, but don’t wait too long after that. Grapes tend to “weep” from their pruning cuts if they are pruned after they begin to break dormancy in the early spring. The weeping is harmless, but it bothers some gardeners to see it happening. Avoid this by getting your grape pruning done in very late winter through early spring.

Master Gardener course

Are you looking for a great gift for your favorite gardener? The Master Gardener course would make a great gift for any gardener who wants to improve their gardening skills, learn more about how plants and soils work together and find better ways to manage pests and diseases in their landscape.

Classes begin on Jan. 18 and continue through March 19.

We have two class sections each Tuesday and Thursday — an afternoon section from 1 to 3:30 p.m. and an evening section from 6-8:30 p.m. All classes will be available virtually, and some will also be available in person and virtually. The same class content is covered in the afternoon and evening classes on the same day. Come learn and grow with us as you make new friends, learn lots of amazing things, gain new skills and get involved in cool gardening projects in the area.

All are welcome to participate in the classes. However, the purpose of the Master Gardener program is to develop trained volunteers who provide Utah communities with unbiased, research-based horticultural education and technical assistance in gardening and home horticulture. You’ll receive 17 class sessions of college-level lectures and hands-on training workshops taught by Utah State University Extension faculty and industry professionals.

In addition to the classwork, students who wish to become a Certified Master Gardener must provide a minimum of 40 hours of approved volunteer service back to their community.

You’ll find more information about the Master Gardener course at https://tinyurl.com/2s4j2jj8.


Join thousands already receiving our daily newsletter.

I'm interested in (please check all that apply)