Pterocarya

( ter - oh - KAHR - ee - ah )

At-A-Glance Information

This genus contains deciduous trees that can reach between 33 and 131 feet tall. They are native to Asia, and are very attractive, fast growing trees that are planted in parks and gardens throughout the world. Commonly called 'Wingnuts', these trees produce handsome foliage and long catkins that dangle from branches in late spring (typically from May through June). Use these as specimen trees, shade trees, or as large background foliage trees.

Pterocarya species and varietals

The genus Pterocarya is a member of the plant family Juglandaceae and includes 6 species. These trees grow best in zones 4-24 (to find your zone, click here: Zone Map).

Pterocarya fraxinifolia (Caucasian Wingnut, Caucasian Walnut)
This species is native to Armenia, Azerbaijan, Georgia, Iran, Russia, Ukraine and Turkey, and reaches about 100 feet tall. Flowers appear on these trees in April and are followed by winged green nuts. Caucasian Wingnut prefers a climate with mild winters and mild humid summers.

Pterocarya hupehensis (Hubei Wingnut)
These trees are native to China, where it grows along moist streambanks. Trees typically reach 65 feet tall, and have dark grey to pale grey fissured bark. Flowering occurs from April through May and fruits are ripe in August in the tree's native range.

Pterocarya rhoifolia (Japanese Wingnut)
These trees are widely distributed through Japan, and are also found in China. These trees love areas near riverbanks and mountain streams, and flower from May through July. Yellow-white wood is soft and light, and is used to make traditional Japanese footwear.

Pterocarya stenoptera (Chinese Wingnut)
These trees are native to China, and reach 40-90 feet tall and 30-50 feet wide at a quick pace. Branches are heavy and spreading, producing small, winged nuts (hence the common name). These trees are great candidates for areas with compacted soils in high-traffic areas. Roots are aggressive.

Caring for and pruning pterocarya Trees

Plant Wingnut trees in direct sunlight. An ideal spot in the landscape is one that receives between 6 and 8 hours of sun exposure each day. Ensure that the planting site has enough space to accommodate the full size of the tree, which can reach up to between 10 and 100 feet tall. They love well-draining soil, and can tolerate loamy or sandy substrates. Pterocarya prefers soil to be slightly acidic to neutral, with a pH of between 5.5 and 7.0. If local soils are particularly poor, or if they do not drain well, make sure to amend the planting site with plenty of organic material and/or sand before installing trees to give them a solid head start on growth. Apply a thick layer of mulch around the base of trees to suppress weed growth, increase soil moisture retention, and help to regulate soil temperatures. Newly planted trees should be watered regularly to help them establish a strong root system. When mature, they prefer soil to stay a bit moist, but can get by on just rainwater during the wetter months of the year. Deep water during the drier season.

Prune trees in late wintertime or early spring, removing dead, damaged, diseased, or crossing branches. Remove suckers and seedlings as they appear. Fertilize with a dressing of organic compost around the base of trees in springtime. This is typically enough nutrients to support the growth and flowering for the season, but if trees seem stunted or are otherwise struggling, they may benefit from a feeding with a balanced, slow-release fertilizer in spring or mid-summer. Avoid over-fertilizing, which can lead to excessive foliage growth and possibly harm the tree.

Propagation

Pterocarya can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your Wingnut Tree, follow the instructions below:

Propagating Pterocarya by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. If you don't have any potting medium on hand, you can make some. Just mix together equal parts (by volume) moss peat and horticultural-grade sand or grit sand. You will also, after a few weeks, need individual 3-inch pots for each seedling that grows.
Harvest your seeds in late summertime or early fall, when they begin to be released from their attachments naturally. These trees produce long panicles of female flowers, which when pollinated will produce winged nuts. They will begin producing seeds when they reach between 10 to 20 years old, depending on the growing conditions and species grown. Each panicle typically will hold between 20 and 80 seeds. Place collected seeds in a paper bag, and bring them indoors to work with them. They can be stored in a cool, dark, dry place for about a year before losing viability.
Place seeds in a container or plastic bag filled with moistened peat moss or sand and place the container in the refrigerator. Leave it to chill for between 60 and 90 days' time. After this period has passed, take seeds out and sow them.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Female flower panicles (pictured) are long and dangle from terminal points of new growth, while male panicles are denser, shorter, and grow on lateral or old growth.