A: Since your holly shrubs have “settled in and grown” I don’t think you are doing much wrong at all. It could be the plants themselves. Holly plants are “sexed.” You’d have needed to plant both female hollies that produce the berries and a male holly plant to pollinate the female when it’s in bloom. If you unknowingly planted only male plants, then, no, you will never get those cheerful red berries. Or if you only have female plants and there’s not a male plant in the area, then, again, no berries.
The way you tell if you’re getting female or male plants is usually by the name of the plant. China girl or blue girl denotes a female plant. Blue boy or blue prince equals male plants. Responsible growers do pay due diligence and tag the plants appropriately. There are a few oddities in the holly world that are able to produce berries without the stress of sexing, but be sure to do the necessary homework to make certain you get the correct variety.
Now, if your plants weren’t tagged, you might have only one sex. If you have all females it’s as simple as planting a male in the area. If there are only males, then you have a hard decision to make. Sacrifice a couple of them and insert true females or find another environmentally acceptable place for a new stand of females. One sure way to know you’re getting female plants is to buy ones that are already sporting a few berries. Then, there’s no doubt as to their sex.
Since you say the plants have done well, I don’t think the way you are taking care of them is a contributing factor. But just in case, be sure to offer your holly the appropriate fertilization. These plants are “acid lovers” and since our soils are on more of the alkaline part of the scale, be sure to treat them to a fertilizer giving them the acid they require. You can find fertilizers touting that information on the label saying things like “for acid lovers” or “evergreen fertilizer.” Most nurseries will stock an appropriate food for plants that need a boost so it’s not difficult to find.
However, since your hollies don’t have any berries at all, I’m betting it’s because of a sex thing and easily fixed for the most part.
Tracey Fitzgibbon is a certified nurseryman. Send your questions to Digging In, Rio West, P.O. Drawer J, Albuquerque, NM 87103.