by Dave Bogan

This article appeared in the April 2005 issue of the Evansville Bonsai Society Newsletter. Dave has a fantastic seju elm forest. Since several members expressed interest in getting some seju elms from Hollander's Tiny Trees for their personal use, I thought I would run this informative article - ED.

Still somewhat of a rarity in Bonsai. Information on this sub species of Elm is even harder to find. Even on the web, try a Google search, you won't find any real specific species related information.

I fell in love with this elm several years ago. A species that is perfect for Bonsai. Excellent branch ramification, very very small leaves, perfect Bonsai material. Rarely seen in nurseries or Bonsai stores, they are available; you just need to search for them. Luckily in our area, one of our members (Greg Hollander of Hollander's Tiny Tree Farm) has been growing them from cuttings for several years. Cuttings, due to the fact the species was first obtained via a "sport" or unusual growth on a regular tree.

A very hard species to research and very few articles exist. Here is the only real notation I have found.

Ulmus parvifolia 'Seiju' This sport of 'Hokkaido' was introduced by Carl Young of Lodi California. It has all the good qualities of 'Hokkaido' in a larger plant. The leaves are identical except they are about 1/2 inch and the plant may reach about 10 feet if planted out. It has the same deeply fissured corky bark that begins roughening in about 2 years. The wood is stronger and more flexible and can be wired. Grows quickly, about 18 inches a year. This cultivar is best for Shohin through medium sized bonsai. It should be large enough to allow the bark to fully develop, but also can be grown to six inch caliper in a reasonable amount of time

The above article really leaves something to be desired. In the 10+ years I have grown this species, I have found a few issues you should be aware of before attempting to grow them.

Typically a fast grower if grown in the ground. As with many other species, once in a Bonsai pot, a growth rate (primarily trunk area) drops off quickly. In the ground, trunks will develop rapidly. If grown in the ground, I advise annual pruning for direction & style if possible to avoid swelling or unusual growth at the pruning points (see pruning). Luckily, once in pot culture, the individual branching and ramification continues to happen quickly. The Seju develops very small leaves. No leaf reduction required here. The leaves will slightly reduce over time in Bonsai ( down to 1/4") but the initial full growth leaves are only around 1/2", so don't attempt leaf reduction procedures as it's really not necessary.

Seju has many of the normal elm characteristics. In the bark department, it is similar to the "cork bark" elm in many ways. Maybe not quite as fissured, the Seju will develop a corky bark in time especially on the lower trunk areas. For those of you that have grown "cork bark" elms, you're probably already aware of the potential for pests and diseases in the corky fissures of the bark. Maybe not quite as susceptible as the "cork bark", they should still be treated for the dreaded bore annually. I apply a bi-annual treatment of granular systemic to the soil, and to date have only had bores in one Seju. Just be aware it can & probably will happen if not treated. The only other problem I have experienced is the occasional fungus gnat infestation. The eggs of fungus gnats are laid in fall. In early fall I make sure I soak the bark areas with "Pyola" insecticide over several consecutive weeks. This is a light dormant oil (canola oil) with pyrethrins insecticide mixed in. This seems to eliminate the fall eggs, and since using this treatment I have not experienced any more fungus gnats.

Pruning: An undesirable characteristic (as with cork bark), Seju can develop an unusual looking or swelled appearance especially in areas of heavy pruning. Try to limit your hard pruning to young trees. On older specimens, you can diminish this area slightly by removing some of the corky bark in the swelled area, but it may stand out just as much due to the bark differences.

An excellent species for pruning as it will back bud readily in all areas including the trunk. I have hard pruned mine; and within 3 years, obtained decent ramification due to its rapid growth of foliage and small limbs. I will caution you to remove excess growth. Typically when pruned (especially if hard pruned), they send out a multitude of new branches around the pruned area. Reduce these down to a couple to help avoid swelling at the pruned areas. Remove all extraneous trunk growth as it appears. In spring, due to the rapid new growth rate, you will need to occasionally thin out some areas to allow light penetration to the inner areas. Small new branches will die off very rapidly after the spring growth flush if they don't receive sufficient light.

Wiring: The article mentions the wood is more flexible. True if the growth is less than 2 years old. The wood becomes brittle with age. I have accidentally bumped my tree and broken off branches. Just a word of caution, be careful wiring. I have better luck with clip and grow, once the tree is over 4 or so years old. Branches seem to hold position well if the wire has been left on the proper amount of time. As with many deciduous species, wire longevity is directly tied to growth rate. Watch closely for rapid spring growth as wire scars are hard to heal on this species.

Roots: As with most of the elms which have been started from sports, the roots are very fleshy. I definitely recommend building your root system slowly; starting when the tree is young, you can remove large fleshy roots, but be cautious and only remove a couple per year. The roots are similar in texture to buttonwood in the fact they seem like soft spaghetti and break off very easily. Due to their fleshy nature, be careful when cleaning the soil off the root system. No root hooks here, wash out the old soil with a hose and you'll experience less damaged or broken roots. Excluding the large fleshy roots, I have no problems removing almost 1/2 the root system if required.

Fertilizer: In the early stages, feed well and feed often. In the growth & establishment phase, I fertilize weekly @ full strength. They will thank you with rapid growth. As the tree evolves, start cutting back on the fertilizer – especially nitrogen. On established or finished trees, I fertilize every 6 - 8 weeks. As with many deciduous trees, additional fertilizer generally can result is extraneous growth that needs more attention and pruning, a situation you don't need in finished trees.

Again, a little hard to find but well worth the effort.

I have had the pictured grove (picture from 2005) setting for well over 10 years, and it has become a favorite in my collection. The picture really doesn't do it justice but maybe it will encourage you to try one. On a further note, it was re-potted two years ago into the brown shallow pot that looks a lot better. I also have several single trees which are becoming very nice individual informal uprights.

Once established, they are very easy to maintain. I simply perform a slight pruning two or three times a year (depending on fertilizer added) for shape & to maintain the openness and it looks great. As with most groves, once it's established I only need to re-pot about every four or so years, depending on the species. Then it's a simple matter of pruning off the bottom and sides, & back into the same pot it goes.

Keep in mind, since it was derived from a sport, you can not grow this species from seed, as none are available. It must be started from cuttings.

Location: Full sun. I have never experienced any growth reduction or leaf problems. It would probably be fine in slight shade, but I feel the full sun light makes it stronger and reduces the leaves even more. My expressed opinion is if they start spring in full sun, they will be able to withstand full sun all year. I feel moving a tree back and forth stresses and confuses it - another story.