How to Grow Holly
By: Julie Day
“Deck the halls with boughs of holly” may be a traditional Christmas carol, but holly has enjoyed a long symbolic history in other cultures as well. From decorating statues of Saturn—the Roman god of the harvest—to providing medieval protection from evil spirits, to offering shelter to imaginary woodland creatures and fairies, holly boughs and berries have brightened up the winter months since ancient times.
In the garden, hollies (Ilex sp.) are a striking choice that provide year-round interest and serve as great foundation plantings or hedges. There are hundreds of varieties of hollies, ranging from tiny shrubs less than a foot tall to towering trees reaching 70’. Most are hardy to zones 5 or 6, with a few varieties hardy to zone 4.
Hollies are known more for their berries than their small white flowers. You can find red, pink, blue, orange, yellow, and white berries, with some varieties more showy than others.
The shrubs and trees themselves may be rounded, pyramidal, columnar, or weeping in form. Leaf shapes range from the large, spiny leaves of holiday tradition, to tiny, smoother ones that are often mistaken for boxwood.
Sorting out the hundreds of varieties and hybrids of hollies can be a dizzying task. In general, hollies can be divided in the following main groups:
- English Holly: (Ilex aquifolium) These are the varieties most commonly associated with the Christmas holiday. With glossy, spiny foliage and variegated options, they can make a bold statement both indoors and out. Popular varieties include ‘Angustifolia’ and ‘Gold Coast.’
- American Holly: (Ilex opaca) Similar to English holly but with duller leaves. The trees tend to be pyramidal in shape and make great barrier plants. Common varieties include ‘Carnival’ and ‘Greenleaf.’
- Japanese Holly: (Ilex crenata) Include the distinctive ‘Sky Pencil’ as well as dwarf spineless varieties such as ‘Yaupon’ and ‘Helleri.’
- Chinese Holly: (Ilex cornuta) Best known for the large, glossy, spineless varieties such as ‘Burford’ and ‘Carissa.’
- Hybrid Holly: Includes countless options, one of the most popular being the Meserve hybrids (Ilex x. meserveae) which cross English and Chinese hollies with the more cold-hardy ‘Prostrate (I. rugosa) variety. Popular Meserve hybrids include the Blue hollies and ‘China Girl.’ A common natural American holly hybrid is ‘Fosteri’ (I. x attenuata).
- Deciduous Holly: These varieties lose their leaves to display branches laden with berries in winter, giving rise to the common name of Winterberry (I. verticillata), as well as Possumhaw (I. decidua). Popular varieties include ‘Red Sprite’ and ‘Jim Dandy.’
- Miscellaneous Evergreen Varieties: As if those above weren’t enough, there’s Inkberry (I. glabra) as well as Asiatic varieties such as Longstalk (I. pedunculosa) and Perny (I. pernyi).
Plant Gender and Berry Production
Hollies have male and female plants, with only the females producing berries. Female plants must be pollinated by male plants that bloom at the same time.
In developed neighborhoods, there are often sufficient male shrubs in the vicinity, but if your plant is not producing berries you may need to plant a pollinator. A good guideline is that you need at least one male plant for every ten females. Many cultivated varieties have male and female named counterparts, such as Blue Girl and Blue Boy.
Some commercial growers solve the pollination problem by grafting together both male and female stems, or by planting them together in the same pot. Be sure you know the plant’s gender before purchasing a holly shrub, so you won’t be disappointed.
‘Helleri’ reaches 4’ tall and resembles a small boxwood
Tips for Growing Holly
- Hollies don’t transplant well, so consider the plant’s full-grown size when choosing your planting spot.
- This also means it’s difficult to transplant one from the wild, so buy nursery-grown plants instead.
- Hollies can be propagated from cuttings of year-old growth. Propagation from seed is difficult but not impossible.
- Plants usually bloom within 2-3 years. Berries may take longer, so be patient!
‘Soft Touch’ is a dwarf spreading variety that grows only 2’ tall but up to 8’ wide.
Planting and Growing Conditions
While many of us go on a mad search for holly branches and berries around the holidays, holly shrubs are best planted in spring, right before they start growing but with plenty of warm weather on the way. Hollies like:
- Light: Holly plants to best in full sun.
- Soil: Well drained loamy soil that is slightly acidic. If your soil is very heavy, add some organic material to lighten the texture and improve drainage.
- Water: Hollies like a moderate amount of water, usually adequately provided by rainfall. Water weekly during drought.
- Mulch: Several inches of mulch to prevent freeze-thaw damage to the shallow roots. Apply mulch in a circle as wide as the branches.
- Fertilizer: A dose of fertilizer in spring and fall can help keep plants healthy.
Hollies respond well to pruning and make great hedges or geometric shapes. Correct bare spots, caused by over shearing, by occasionally making deeper pruning cuts to allow light to penetrate the plant.
Take care to prune branches only back to a growth bud – if you completely remove a holly branch or stem, it may not fill back in. The holidays are a great time to prune hollies – then use those cuttings to deck the halls!
The striking tall column of ‘Sky Pencil’ make it a good container plant.
Pests and Diseases
- Birds love holly berries, but thankfully they prefer them after several freezes, which usually means they wait until late winter to eat them.
- The most common diseases affecting hollies are black spot, phytophthora leaf and twig blight, and sooty mold.
- Problematic insects include holly leaf miners, bud moths, and red mites.