Mystery shrub is likely a Silver Queen euonymus
Q: This shrub was here when I bought my house a few years ago. The new leaves it puts out are green and then turn this variegated color of white and green. I haven’t been able to figure out what kind of plant it is. It also seems to have gotten sick over the past year. Spots on some leaves and a black dusting on others of what I’m guessing is mold. I’ve tried spraying it with neem oil, but it hasn’t gotten any better. Any idea what kind of plant it is and how I can help get it healthy again? — S.C-B., Albuquerque
A: I’m quite confident that the shrub you have is a variety of euonymus called Silver Queen. It’s defined as wearing green leaves that have creamy white edges.
I’m thrilled for you, since the photos you sent don’t show any euonymus scale on the branches, so you’ve been doing something right. Yes, there is some damage, the spotting and what you call mold, but all the buds and the majority of leaves look good to me.
From all the reading I did, I’ve learned that euonymus are prone to mildew, which I didn’t know. I suggest that if you water the shrub from overhead consistently — stop. It’ll be healthier to keep the watering at ground level.
Also, I’ve learned they are heavy feeders, meaning you should think about putting this shrub on a calendar feeding schedule. Since the euonymus is an evergreen, I’ll suggest offering an evergreen fertilization, not constantly, but more as a treat for one or two of the feedings during the growing season.
If you apply a water-soluble food that can be sprinkled on the foliage, do that very early in the morning or well after the heat of the day. Having water containing fertilizer sitting on leaves with hot sun hitting it is a definite no-no. I’ll recommend you apply the fertilizer at ground level for the health of the shrub.
I also learned that euonymus is susceptible to mold — more mildew than anything — and also mites. Reading suggests that you invest in a broad spectrum rose insecticide/fungicide and following label instructions treat the euonymus as if it was a rose. That will help keep the shrub healthier, perhaps eliminating the dark spots worn by some of the leaves and keeping the mold at bay.
The photos show a wall close to the shrub. Does it get a lot of reflective heat? If so, keep the shrub on a good watering schedule, remembering to keep the water at ground level.
I’m amazed that your shrub doesn’t show scale insects, so again you’re doing something right or very lucky with the euonymus. So keep it up, tweak its care just a bit and see if it makes a difference. Good luck.
Q: Do you know what kind of trees are blooming right now in Albuquerque? I see trees all over with white blossoms. They almost look like pear trees. — J.P., Albuquerque
A: You are correct that the bright white blooming trees that are making such a big show this time of year here in Albuquerque look like pear trees because they are a very close relative, ornamental pear trees. Probably a variety named Bradford.
Sure some in bloom now might be actual fruiting pears but the majority of what’s flowering right now wearing the bright white blooms are the ornamental variety. These trees are pretty darn sturdy and once established do grow well here in our climate.
Yes, they do require consistent watering through the growing season, but since they don’t fruit, the water requirements aren’t quite as stringent as their fruiting relatives. The ornamentals do offer a good green foliage in the growing season, and then you get the added advantage of nifty autumn color come fall. Right now though, they are putting on quite a show, especially if you take the time to watch for them. They do seem to be everywhere.
Happy Diggin’ In watching spring unfold!