Holly

One of the plants long associated with winter holidays is holly, said to bring good luck to a home. You may picture holly as having thick, dark green, glossy leaves that remain green all winter.  Others of you may know hollies that you call winterberry or possumhaw, which lose their leaves in the winter to display branches lined with beautiful berries.

There are over 600 species of holly, from many parts of the world. Hollies may be widely divided into groups, English hollies, Ilex aquifolium, American hollies, Ilex opaca, Blue holly, Ilex meservae, Chinese holly, Ilex cornuta, Japanese holly, Ilex crenata, possumhaw, Ilex decidua and winterberry holly, Ilex verticillata. There are other species grown for ornamental use and each of the above species has numerous named varieties.  Hollies species are also crossed to provide some ornamental hybrids.

American and English hollies make excellent landscape trees.  Blue hollies and others are used as landscape shrubs and specimen plants.  English hollies are often trimmed into hedges.  The deciduous hollies are excellent as shrubs for winter color and for naturalizing.  Winterberries will grow in wetter areas such as rain gardens and pond side plantings. Hollies are deer resistant.

Most evergreen holly leaves are thick and glossy green.  Many evergreen species have toothed leaves, with a spine at the end of each tooth.  Some however, have smooth, nearly oval leaves.  There are some variegated varieties.  Hollies that drop their leaves in winter generally have long, oval leaves with smooth margins.

All hollies have one interesting feature.  Male and female flowers are born on separate plants.  To get those beautiful berries you will need at least one male plant for every 10 or so females.  Only female plants have berries.   The holly flowers are small and whitish.  They have a sweet scent that attracts bees and other insects to do the pollinating.  You can tell male flowers if you look inside the flower and see yellow pollen.  Female flowers already have a round, green swelling at the base of the pistil that becomes the berry.

Holly plants may not flower for several years after planting so it’s important to label the males so you will know if a male dies and you need to replace it. Pay attention to catalog descriptions or label information, which tells you what type of male plant you need for each female you buy.  Blue hollies are needed to pollinate blue hollies and possumhaws are needed to pollinate possumhaws and so on.  Even within a group some plants will be better mates for each other.

Most holly berries will be red or black, but there are orange, yellow, coral, pink, blue and white berried varieties on the market.  Some people are not interested in the berries, only the evergreen foliage and for them there is no need to worry about male and female plants.  There are a few varieties of hollies that will produce berries without a male.

Birds like holly berries later in the winter, after they have been frozen several times.  This allows you to get a good winter show and still feed the birds.  Birds also like to shelter in evergreen hollies during the winter.

Holly culture

Both deciduous and evergreen hollies prefer slightly acidic soil but can be grown in more alkaline soils with the right fertilizers.  They like rich, well-drained soil in full sun.  The winterberry group will tolerate damp areas, although it will also do well in average garden conditions.  Evergreen hollies like some protection from winter winds, at least while they are young.

The evergreen hollies are slow growing, the deciduous much faster. In the spring both benefit from some acidic fertilizer.  You can use a slow release acidic fertilizer that is formulated for holly, rhododendrons and so on that is commonly found in garden stores.  Cottonseed meal, pine needles and other acidic organic mulches are good. Keep holly watered during dry spells.

Hollies vary as to hardiness; the winterberries and American holly are probably the cold hardiest.  Check the zone hardiness of any variety that you buy.  Some forms of holly are considered to be invasive, spreading by the berries.  All parts of the holly plant are poisonous so keep that in mind when you select a planting location.

Holly is not just for winter decorations, it’s an excellent landscape plant for all seasons.