This post focusses on the basics of winged elm bonsai. Below is an article I put together for the most recent Indianapolis Bonsai Club newsletter, along with some photos of a couple of my winged elms.
Hope you enjoy. By the way...please check my for sale page. I've added new material and I will be rolling out a new site soon with more content and photos.
I honestly cannot think of better native deciduous material than the winged elm. They are tough as nails and develop quickly, as you will see in the photos.
The first tree featured spans about 3 years of work. I will be removing the highest section of deadwood and shortening the canopy this summer.
The crazy root at the left will be coming off.....just in case you thought it looked out of place.
As you can hopefully see, these are great trees with loads of character. I hope you find the article below helpful and possibly applicable to other species of deciduous trees.
The Winged Elm aka Ulmus Alata is a deciduous species native to the United states. It ranges from the upper Midwest (Central Illinois/Indiana) into the south and southeast and as far west as Oklahoma.
Aside from the common Chinese Elm, most elms are not typically considered optimal species for bonsai. Although readily available they are considered a “pioneer species” rife with problems such as branch die back. When trained properly native elms can be very rewarding.
Placement & Watering: Winged elm thrive in full sun but also will tolerate almost any growing condition. My own winged elms receive full sun in the heat of summer from sunrise until evening. Well drained soil and attentive watering are essential. I generally water only when dry or almost dry. I water in the morning hours or mid-day primarily because the trees need access to moisture during the hottest part of the day. If the tree is somewhat dry in the evening I will not water until morning unless it is windy.
Soil: I prefer a mix free of organic material (turface or akadama or a 50/50 mix). My “elm mentor” Mike Flanagan has collected this species for 30 years in Central, Oklahoma. He has successfully relied upon a mix of composted pine bark and haydite. I also use a top dressing of moss or milled sphagnum moss. This aids in not only reducing evaporation, but protects the upper +/- 30% of the soil from drying. This provides a greater volume of growing area within the pot for roots to colonize. Without the top dressing, that area would have been unavailable to the root system and likely been home to weeds.
Fertilization: Winged elms are strong growing and require generous feeding, I use a basic 20-20-20 for developing trees and an organic cake/fish & seaweed for trees in refinement. The most important feeding is during late summer and Autumn. Trees build strength and set buds for the next spring. Fall feeding is especially important if you plan to repot the following spring.
Repotting: This species needs repotted every 1-2 years. Failure to repot after 2 years creates the risk of branch die back. Although I am unsure of the exact horticultural issue, I have learned from experience that branch loss typically occurs in underfed trees and or those that have gone past 2 years without repotting. I presume that as the roots are constrained, the tree sheds branches that it may not be able to maintain with a restrained root system.
Collecting: Winged elms can be reliably collected from Late winter through mid-spring with little set back. Collecting should occur when a hint of green begins emerging from the buds at the branch terminals. Although elms can be pruned hard at the time of collection, its generally better to leave branch terminals intact for 1 year after collecting. If the tree is responding well it can be pruned and basic styling performed during the summer. An alternative to pruning at the time of collecting is to hard prune the tree 1 year prior to removing it from the ground. This gives the tree 1 year to regenerate foliage. An important concept to remember is that foliage = root growth in deciduous trees! I have also learned that the winged elm requires light immediately following collection. In the warmer climate of Oklahoma, elm can be left out doors after collecting. However in the Midwest they require some shelter from excessive cold. For many, that is a dark cool garage. Success is limited in this scenario.