As we do on many Thursdays, I checked in with our gardening expert Alison Arnold.
Q: You were talking earlier that it’s usually November when people notice their holly trees don't have berries but that now is the time to look into why this might be happening…. Tell me more about that?
A: Yes and we are talking about the native American holly and yes.. so when the question comes up about why a holly doesn’t have berries its important to rule out the most obvious question - is the plant flowering at all?
Q: That seems like an obvious and good place to start doesn't it?
A: Well it does because of course if it doesn’t flower it doesn't fruit … OK so if it’s not flowering there are a few things to check out.. One is age.. if it’s a young tree it may not have reached maturity or flowering age yet – they need to be at least 3-5 years from seed to begin blooming.. Also If the plant is pruned at the wrong time the flower buds - which are really small …are cut off. Also if the plant is in heavy shade there wont be good flower set.. and thus no fruit.
Q: OK so it sounds like holly flowers aren’t real showy and can be easily overlooked?
A: Right.. the flowers are about 5/16 of an inch across and typically open – between late April and first of May depending on the temperatures. Also Hollies are dioecious – which means male and female flowers are on separate plants and so it could be that you have a female plant but no male plants or flowers nearby.. or you have a male plant. This is usually the case.. but it’s hard to know unless you can look at the flower.
Q: Alright then.. how do you tell the difference?
A: So you’ll be looking at four rounded creamy white petals surrounding a green center. You want to pay attention to the green center.. in the female flowers this is the ovary and will protrude somewhat and be large and obvious. In male flowers it will be much smaller and more of a simple button shape. The male flowers also carry the pollen on the stamens and so you’ll see that too.
Q: Wow – do you need a hand lens to see this?
A: No.. you just need to catch it.. of course if you do miss the flowering and it’s a female and the bees have done their good work of pollination the small developing bright green berry will be pretty obvious.
Q: Are there other reasons why a flowering holly wont set fruit?
A: Dry weather can also cause flowers to drop off and cool weather can either kill flowers outright or reduce pollinator activity..
Q: OK.. so this is really helpful knowing about male and female holly plants.. and so Im wondering if there is ever a situation when it would be DESIRABLE to have only a male plant of something?
A: Well.. yes there is.. Ginkgoes for instance are also dioecious and so If you’ve ever been around a female ginkgo tree when it is in full fruit .. by the strong smell of the fruit you’ll quickly realize why a male tree would be preferable.. especially in your own landscape..
Alison Arnold is Agriculture Extension Agent with the North Carolina Cooperative Extension. Alison thanks very much.
