Growing Concerns 542: Acorn trees grow fast, and others too

Late Fall!

Tiny acorns yield massive trees in relatively short time

Dear Janet,

I was glad you wrote, "Trees grow faster than people think they do. Beeches, oaks, ginkgos and others are mistakenly assumed to be slow growers, and so are sometimes overlooked as potential shade trees." I planted acorns 30 years ago. The bur oaks and white oaks that grew from them are massive trees now. It's amazing how fast they grew, wonderful to see them now and know I planted them.


Dear M.G.,

It's been said, "It's good to watch things grow, it gives you faith in life." You're a great example of that, as is G.V.A.  who in his seventh decade is still planting new hickories, using the sweetest nuts from the best trees on his property.

Who knows where the notion originated that majestic trees, most desirable for those who want to plant a legacy, require many generations to attain good size? Certainly the experts know otherwise.

Professor Leon Snyder of the University of Minnesota, whose life work revolved around plants for Great Lakes landscapes, wrote in "Native Plants for Northern Gardens" that white oak is reported to be slow growing but in good soil the growth is comparable to other shade trees. Professor Michael Dirr, author of "Manual of Woody Landscape Plants," a standard reference in universities and nurseries all over North America and Europe, reports that red oaks grow as fast as red maples at 2 feet per year and pin oaks grow even faster, 12 to 15 feet over a 5 to 7 year period.

Given the right environment, a tree can even overcome slow genes. A ginkgo tree, writes Dirr, is generally slow to medium at 10 to 15 feet over a 10 to 12 year period, but will grow very fast with adequate water and fertilizer -- which explains one in my care that has been rocketing along at 18 to 24 inches per year. Similarly, while the English expect European beech to grow 18 inches per year, and I can, too, after watching my own 6 foot tricolor beech reach 20 feet in eight years, Dirr reports it as "much slower growing in the South."

Longevity may work against a tree's growth rating. Dirr reports that even though we see a white oak put on 12 to 15 feet in a 10 year period, it slows down once it's 20 to 30 years old. So, M.G., your white oaks may have grown 50 feet in 30 years but will be only 100 feet tall after 200 years, an average growth rate of 6 inches per year. Along that same line, Dirr writes that even if a gingko attains a fast rate of 18 inch per year as a youth, it can be considered slow if you count its growth over many years. He cites one he admires in London's Kew Gardens, recorded as growing only 56 feet between 1762 and 1890.

Short reports

You missed some red fall color plants!

G.H.  wrote to tell me I should have included trees such as the Sargent crabapple in his yard, for red fall color. "It's not the leaves, it's thousands of tiny red crabapples, which will stay red and keep the tree colorful right through winter."

My previous article was devoted to fall leaf color, G.H., but I agree persistent fruit is a great attraction in the winter landscape. Alongside your tree we can list crabapples 'Molten Lava' and 'Adams,' mountain ash (Sorbus aucuparia), Michigan hollies (Ilex verticillata) and cranberry bush viburnum (V. trilobum).



Green thumbs up

to speaking up.



Green thumbs down

to leaving garden soil bare and exposed over winter. Winter rains pulverize soil particles and can undo all you did in a year to attain loose, well drained soil. If you must follow that ridiculous and destructive urge to remove every fallen leaf from a property, topdress bare beds with mulch, compost or evergreen boughs to absorb the impact of weather.


Originally published 11/22/03