You plant a female holly tree and count on those red berries come winter. You feed it, water it…but no luck: No berries, just empty branches. Why? Because hollies is what’s called dioecious, meaning they has separate male and female flowers on different plants. For a female tree to bear fruit, she require some pollen from a local male tree.
There’s nothing wrong with the tree; it’s just biology. The varieties in this group need to be planted close enough to cross-pollinate; the chart above indicate which ones pollinate one another. It’s not just about the individual plant but also how the trees relate to each other, for example, one male holly can pollinates up to five female plants if they are within fifty feet of each other. The closer you put the male (within ten feet of the females, ideally) the better chance there is of having a good crop as bees don’t like traveling very far.
Why Your Holly Has No Berries
Distance is important, but so is timing: You want both trees to bloom at the same time or else there’s no pollination. One blooms in mid-May and the other blooms in late April. No go. This chart helps you pair things up right by grouping them into early, mid-season, and late bloomers. An English holly should of been paired with Blue Prince or Edward J. Stevens, while the American holly match nicely with Jersey Knight. Don’t mix an early bloomer with a late bloomer; or you won’t get any fruit because flowers never bloom at the same time.
Soil conditions are another factor that influence how well holly flower and grows. Ideally, holly likes acid soil, ranging from pH of 4.5 to 6.0. If you have alkaline soil, it may stunts the plant. This limits flowers and nutrients which leads to what’s called nutrient lockout. A poor root system won’t support fruiting even if there is a compatible male partner nearby for pollination. Test your soil first so you don’t set yourself up for trouble later. Sulfur helps reduce the pH if your soil is on the high side and creates habitat the holly needs.
Once they successfully get pollinated, that’s when care shifts. Don’t prune in summer or spring. If you do, you will remove the flower buds needed for next year’s crop of berries. Shape the tree then, after harvesting its berry sprigs in winter. Throughout the growing season, water deeply and be sure to cool roots with a three to four inch layer of mulch. Consistent moisture prevent the berries from falling off prematurely.
Thank goodness for attracting pollinators: Otherwise I might worry about having no branches at all. I plant some catmint or lavender nearby to attract bees. They is out in force from early till midday, moving around in the morning and early afternoon. Avoid spraying pesticides while the holly is blooming as these chemicals kill the very insects that carries the pollen from male to female flowers.
All systems go, and the holly sets on red fruit against foliage that’s still green. Female plants need male plants, too. Get to know them both, and you won’t go wrong. Come winter, you’ll have nice branches to cut up with.