Written by davethetreecenters • July 27 White Birch is Back, and It’s Borer Proof
Back in the days when throwing chemicals at your garden was the standard way to deal with any problem, from lawn weeds to tree diseases or pests, you used to see many white birch trees on lawns. These fast-growing trees were widely planted, especially in the bare gardens of new developments, and they quickly became attractive smaller trees. They were planted as single trees, or as clumps of 2 or 3, which have an especially charming look. Very cold-resistant, they grew well even in cold zones, and their golden fall color was always attractive. Best of all, of course, was the white bark, which showed all year but was especially striking when the trees were bare. Today they are rarely seen, of if they are it is as old, sad looking specimens misshaped by the removal of many branches and trunks. So, what happened?
Common Pests of Birch Trees
Many trees suffer from pests to varying degrees, but white birch is particularly susceptible to two serious ones:
Birch Leaf Miner, a small fly that lays its eggs on the new leaves. The young maggots burrow inside the leaf, eating out the central tissue and leaving a papery husk. This obviously weakens the tree, besides being unsightly, and over time trees decline and eventually may die.
Bronze Birch Borer is a more serious pest because it kills trunks, causing the death of most or all of the tree. This large beetle lays its eggs underneath the bark of the tree, and the larvae burrow through the growing areas (cambium layer) and by preventing the movement and food and water through the tree they soon kill it.
Once routine tree spraying ended, the numbers of these pests grew rapidly, so that today, in many areas, if a birch tree is planted it will usually be destroyed within a few years.
There Are Several Types of White Birch
The group of trees called birch, or Betula, is fairly big, with about 35 species in it They grow all around the north of Europe, North America and Asia. Many of them are grown in gardens, but a few types are the most common, and several have decorative white bark. The most common ones produced by nurseries are forms of the European birch, Betula pendula, often called silver birch. There are several special forms, and this tree has always been widely planted in colder parts of the USA. There is also an Asian white birch, close in appearance to the European tree, called Betula platyphylla. Some selected forms of the Himalayan birch, Betula utilis, also have white bark. White-barked trees also occur in North America, and the most common is Betula papyrifera, which is also called paper birch or canoe birch.
Which Ones are Attacked by Pests?
All these trees, and other birch too, are potentially susceptible to those major pests, and since bronze birch borer is the most serious, let’s focus on that one. Right off, white-barked trees are generally more susceptible to attack, and of them the most likely to be destroyed are the European and the Himalayan trees. But the paper birch is also susceptible, so switching to native trees doesn’t help much, in this case, with the problem. Generally, this pest is more common in warmer areas, but it is certainly wide spread in zone 4, which hardly counts are warm. It’s worth mentioning too that the borer that in recent years the borer has spread into Europe, where it poses a serious threat, especially to the extensive birch forests in Scandinavia.
What Could the Solution Be?
When faced by this problem, and since people still love and want to grow a white-barked birch tree in their yards, what can be done? Since some birch trees of species that can be attacked are not attacked, it is likely that individual trees have different levels of immunity to this pest. When arborists and tree experts know this, there is a pathway to finding those individual trees. This what has been done with the American white birch, Betula papyrifera. Often this kind of work, which takes many years to complete, is done by Universities or governmental agencies, but this time it was the dedicated work of one man and his nursery.
Out in Wisconsin, in the idyllic area of Sturgeon Bay is the Evergreen Nursery Company, Inc. The nursery was started in 1893 by the Pinney family, and it remains a family business. The nursery grew a lot of trees from seed, and back in the 1970s they planted large numbers of Betula papyrifera seedling trees at different locations, with the idea of watching them, and seeing how they grew, and which were attacked or left alone. One of the lots was in New Carlisle, Ohio, and there they planted 240 seedlings.
The Renaissance Birch Trees
Around 20 years later Thomas Pinney Jr., the owner at that time, was out looking at those trees and he saw that one tree really stood out. First of all, after 20 years, it was completely untouched by the borer. Most of the other trees were dead or damaged. But that was not all. This tree had a perfect straight trunk, and it had beautiful snow-white bark. It looked like a winner. Thomas didn’t stop there, though. He took some pieces of that tree and grew a batch of young trees, to plant and observe further. Since these were genetically identical, they would have the same look and borer resistance as that original tree. After 10 years they were still free of it, and their bark was just as lovely. He named his tree ‘Renci’. We don’t know where that name comes from, but it is a rare boy’s name, so it could be someone in his family. The tree was patented in 2002, to protect the nursery’s rights, after all that work and years. Looking for a good name to reflect how this tree marked the beginning of a return of white birch to our gardens, they trademarked the name Renaissance Reflection®, and that is the name this tree is usually known by.
There are other trees in this series. Renaissance Oasis® forms a slightly broader tree, with clean white bark and good yellow fall color. Renaissance Upright® is a narrower tree, and ideal for smaller spaces. All three are borer resistant, and can be relied upon to usually grow well, although there is always a small chance, especially in warmer areas and under very poor growing conditions, that you could be unlucky and still have an attack – nothing in nature can be 100% guaranteed.
Time to Start Planting
If you are looking for a beautiful, fast-growing smaller tree, your problem is solved. These Renaissance Birches have beautiful white bark, elegant forms, either as a single tree or a clump, and they have beautiful golden fall coloring. Free of borers they will thrive from zone 2 to zone 7, reaching 35 feet tall in just 10 years. They grow best in moist but well-drained soil that is slightly acidic. They are tough, though, and will do well in all but very dry, chalky soils. Plant one – you won’t regret it. Not a borer in sight, so welcome back, White Birch, it’s great to see you again.
***If you want to check the availability of any of the plants mentioned here, go to our Home Page, click on the ‘Search’ button in the upper right, and type in your choice – both common names and botanical ones will work. If, sadly, you find the item sold out, click on the ‘notify me’ box beside the size you want, and you will get an email the moment that plant is available again – it’s easy.
