Chapter 98 Ilex spp.
98.1 Hollies
There are two types of hollies, the evergreen species and the deciduous species. Evergreen species include Japanese holly, Ilex crenata, inkberry, Ilex glabra, American holly, Ilex opaca, and yaupon holly, Ilex vomitoria. The main deciduous species include possumhaw, Ilex decidua, and winterberry, Ilex verticillita. Japanese hollies are the most commonly used for bonsai, and are non-native, while the other species are all natives of North America.
A native yaupon holly in the Selby Gardens collection, Florida. Link to original image.
98.2 Soil: General Deciduous / Rich Conifer Mix
Ratio: 3 parts bark, 1 part grit
Add-ins: dolomitic limestone (~5 lbs/yd), Tree-Tone (15 lbs/yd)
pH: ~6.5 (slightly below neutral)
Moisture: Average
Hollies prefer well-draining, preferably slightly acidic soil, but can tolerate most soil types.
98.3 Cultivation Notes
All hollies do better with more more sun; it keeps them from becoming leggy and keeps the leaves smaller. Most Ilex species back bud readily on old wood.
| Species | Evergreen? | Back Buds on Old Wood? | Soil Mix | Light |
|---|---|---|---|---|
| Japanese holly | yes | strong | 2 organic:1 inorganic | Full sun to partial shade |
| American holly | yes | moderate | 2 organic:1 inorganic | full sun to partial shade |
| Yaupon holly | yes | strong | 3 organic:1 inorganic | full sun to partial shade |
| Inkberry | yes | strong | 3 organic:1 inorganic | full sun to partial shade |
| Possumhaw | no | N.D. | 2 organic:1 inorganic | partial sun to partial shade |
| Winterberry | no | moderate | 3 organic:1 inorganic | full or partial sun |
98.3.1 Potting
Repot on the same schedule as conifers and boxwoods.
98.3.2 Pruning
Roots: Hollies can tolerate removal of about 1/3 of the root mass.
Heavy pruning: Cut branches in fall or early spring before growth starts.
Fine pruning: Clip shoots throughout the season.
Leaf pruning: Do not bother. Holly leaves do not reduce in size.
98.3.3 Feeding
I feed my hollies on a routine monthly schedule from spring to late summer with half-strength soluble fertilizer formulated for acid-loving plants.
98.3.4 Pests & Problems
Pests include leaf miners, mites, aphids, and scale but none are really a serious threat. Few diseases affect hollies.
98.3.5 Winter Storage
Store in mulch outdoors. Try to place in a shaded area so buds do not break in a mid-winter warm spell. No other special precautions are needed.
98.3.6 Species Notes
98.3.6.1 Yaupon Holly
Yaupon holly is a native of North America with small gray-green leathery leaves. They make good medium and shohin size bonsai. Yaupons favor the ‘old oak tree’ style when shaping for bonsai. Flowers appear on second year wood in the spring. Yaupon are only hardy in zones 7-9 so a lot of winter protection is required.
To maintain the shape of yaupon holly bonsai, cut the new growth back in spring and summer to two sets of leaves once six to eight pairs have developed. Ramification will require a few years of clip-and-grow training.
Hollies can be cut back to stumps, then regrown to create dramatic tapering trunks. Link to original image.
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