Holly is a common landscape plant and an even more common holiday decoration belonging to the incredibly diverse genus Ilex, which includes more than 400 species of evergreen and deciduous trees found all over the world.
Locally adapted holly seeds or cultivars are relatively easy to grow and are free from disease and insects. They’re incredibly prunable, with dormant buds ready to bury in no time, and many do very well in near-ground rejuvenation when the canopy needs a full reset.
Perhaps their greatest weakness in the landscape is alkaline soils. Like many other trees and shrubs, it is prone to iron chlorosis in highly alkaline urban soils.
Evergreen species need a little protection in winter, especially in the exposed, windy areas of our region. Many holly only tolerate zones 4 or 5 (our area is on the border between zones 5 and 6). Along with evergreen foliage, this overall lack of hardiness can be a recipe for disaster if some thought is not put into landscape placement.
One of the most common problems in growing landscape holly is usually in berry production. Holly is dioecious, meaning male and female flowers come from separate plants. Therefore, the male plant must be pollinated in order for the female plant to bear fruit. A typical recommendation is 1 she to 3-5 females, but I have observed this ratio shrinking to even fewer males.
I am often asked how close male and female plants should be placed to ensure pollination, but I can’t come across a definitive answer based on research. plant in groups that include females of This is because I like how it looks in groups.
But I have often admired holly as a specimen plant for others’ landscape design. In these instances where the individual hollies are farther apart, common sense and observation lead me to believe that for most yards, placing the plants within about 100 feet of each other is close enough.
However, if more separation is required, I think it is likely that this distance could be increased. This is because most holly flowers bloom profusely, with abundant pollinators appearing by late spring during flowering.
When choosing holly for landscape, I tend to lean towards the native. Because that’s my overall preference. Among us, the American holly (I. opaca) is one of the least used and unique. It’s only native to Union County in southern Illinois, but it’s found throughout the South and was a real treat to see on my travels. It will be a small tree-sized plant about 20 to 30 feet.
My favorite landrace is Winterberry (I. verticillata), which is actually a deciduous tree. In the absence of winter foliage, it hosts a spectacular display of bright red berries that persist for most of winter. However, this plant is one of the few that bears fruit, so it can be an important emergency food source at the end of winter.
Among non-natives, I have really enjoyed the Meserve hybrid holly (I. x meserveae) produced by amateur gardener Kathleen K. Meserveae in the 1950s. She created these hardy hybrids by crossing English herring holly (Ilex aquifolium, zone 7) with prostate holly (I. rugosa, zone 3). They are the most commonly available commercial holly to date, with dark green leaves on bluish-purple stems and abundant deep red berries on female plants. , rarely exceeding 15 feet in height.
If you see a gap in your landscape this winter, consider adding one of these charming holly. Visit the Holly Society of America website hollysocam.org for locally adapted species and cultivars.