Ilex, also known as holly, are known for being evergreen, with showy berries over the winter. While this is true of many varieties, it is not true of all of them. All are easy to grow and have wonderful foliage for at least most of the year. Ilex shrubs come in a variety of plant shapes, leaf styles and shades of green. The major care concern with ilex is in pruning, which must be done with a light and accurate touch.
Prune an ilex in the interest of plant health at any time. Identify all dead, sick or infected branches for removal. Snip the branches off at a point just before it joins with the rest of the shrub with clean pruning or lopping shears. Bag diseased plant parts and dispose of them in the dustbin rather than compost, to prevent disease from spreading. Dip shears in a solution of one part alcohol and nine parts water after using, to disinfect them.
Refresh holly shrubs whose growth and appearance has been lacklustre recently to shock it into regrowth in early spring. Tie landscaping markers around all current growth, then remove one third of the stems at ground level. Remove one half of the remaining marked stems the following spring and pinch back new stems by cutting just beyond a bud. Wait until the following spring to remove all remaining old growth stems.
Prune to shape the shrub in general and to increase branching of the shrub, which will, in turn, increase fruiting. Prune ilex plants in early spring, or at least late winter. Take care to prune before the ilex shrub’s flowers, which are often small and easy to miss, are blooming. Trim back excessively long branches to 15 to 30 cm (6 to 12 inches) shorter than the desired length. Select a cut point that is just prior to an intersection with another branch, and snip the ilex branch at an angle.
Always use clean pruning shears for pruning, as the cut will make the plant vulnerable to disease. Wiping blades down with mineral oil should be sufficient cleaning. For shrub health and a longer lasting prune, it is best to prune by hand.