Dwarf Yaupon Holly Care Guide
There are over 400 species of holly, native to regions all over the world including Korea, Russia, and Japan. One of the most commonly used for bonsai is the North American native Ilex vomitoria 'Nana'. Despite its unfortunate scientific name (the berries cause nausea and vomiting if eaten), the Dwarf Yaupon Holly makes for a lovely bonsai.
This cultivar has a rich history of use by Native Americans medicinally as well as practically, to make things like arrows. In its natural environment it may reach 20-30 feet in height. It is also the only North American native plant that contains caffeine – in fact Native Americans would dry the leaves out (which removed the nausea-inducing properties) and make tea from them, offering this "black drink" as a sign of good will to guests.
The foliage is leathery and dark green, with ovate, alternate leaves that are lighter on the bottom and serrated on the edge. The trunk is light gray with mottled, nearly white spots. In spring this evergreen produced small white blooms that give way to translucent red berries that function as food for many bird species.
The Dwarf Holly needs protection from frost, but does enjoy a winter period so if kept outdoors should be moved to an unheated, sheltered location for the cooler months. In its natural environment the holly will tolerate heavy shade, but this may cause larger leaves so a lot of light is preferable for your bonsai. It may be kept indoors (with plenty of light) but will thrive better as an outdoor plant. Semi-shade is ideal in summer to avoid scorching of the leaves.
Ilex vomitoria needs consistent moisture. It should not be allowed to dry out completely, and attention to watering during the heat of summer is especially important to avoid leaf drop and dieback. In the wild the yaupon grows close to water sources like rivers and streams, as well as in drier locations like sand dunes. Good growth is ensured with proper watering of this species. This specimen has a high salt tolerance.
Feeding should be done with care in spring when new growth is most vigorous. Smaller leaves may be encouraged by applying liquid fertilizer at ¼ strength or a tablespoon of organic feed in a gallon of water, every two weeks during March, April, and May. During summer administer liquid fertilizer diluted to half strength every two to three weeks. Yaupon Holly is flexible but a good 20-20-20 is a safe bet.
Styles – this bonsai lends itself well to shaping and pruning, and is suitable for cascade, informal upright, and windswept. It will also easily conform to park tree styles like "old oak tree".
When pruning, keep in mind that the limbs of this tree have a strong tendency to grow upwards, thus wiring or pruning should be utilized to direct growth in the desired way. When new shoots have developed 6-8 pairs of leaves, prune them back to 2 or 3, doing so above a leaf which faces the direction you'd like the branch to grow. This plant buds back readily and will produce profuse new growth throughout the growing season.
Wiring may be done on holly's flexible branches, however raffia or other protective material should be used to avoid damage to the bark. Wire between spring and fall.
Ilex vomitoria is seen frequently in nature and can be collected in early spring. It can also be grown from seeds or cuttings, although seeds may take a long time to germinate. The cuttings should be softwood taken from the current growth season. Collect these in late summer to early fall, apply rooting hormone, and keep in moist soil in a shaded spot.
Dwarf Holly bonsai should be repotted every one to two years into a well-draining soil. Be conservative with root pruning, removing no more than a quarter of the plant's root system.
Insects/Pests & Diseases
Profuse fruit production can weaken holly, stressing the tree and making it more vulnerable to pest and disease. Limiting the volume of fruit on the tree can help circumvent this problem.
Aphids, scale, mites, or leaf miners may attack new shoots on the bonsai. Scale must be removed manually with a sharp knife, or by dabbing them with rubbing alcohol. After applying the alcohol they need to be removed because the protective shell harbors the eggs, so if allowed to hatch the life cycle will begin all over again.
Other pests can usually be washed off with a spray made up of a teaspoon of dish liquid mixed with a quart of warm water. Spray foliage until runoff occurs, then rinse with a spray of plain water.
A non-toxic insecticide may be applied every couple of months to keep pests at bay. Proper watering and feeding will help keep your bonsai healthy and resistant to problems.