Knoll Gardens - Specialist Grower of Grasses and Perennials

The Return of the Elm

An opportunity to restore some of Britain's lost Elm heritage.
The Princeton Elm: 80 Years of Success

Highly Resistant to Dutch Elm Disease.

Eighty Years of Success in the Landscape.

USDA National Arboretum Tested and Approved.

Extremely Tolerant of Harsh Environmental Conditions.

Thrives in Any Soil type.

Extremely Fast Growing.

Roy Lancaster plants the first tree in English soil at Knoll Gardens

Modern and perfected rooting technology has allowed us to reliably produce own-root Princeton elms for the first time ensuring that all our disease resistant elms are
'Princeton from top to bottom'. Roger Holloway of Riveredge Farms of Atlanta, Georgia USA and Neil Lucas of Knoll Gardens of Wimborne, Dorset have teamed up to reintroduce the elm tree to the U.K.

First brought to the U.K. and shown at Chelsea Flower show in 2001 and 2002 where they attracted much attention, the very first tree to be planted in English soil was at Knoll Gardens.

Other elms have gone to the National Trust and to the Royal Horticultural Society Gardens at Wisley.

Princeton Elms supplied by Knoll Gardens have also been planted by HRH the Prince of Wales at
Highgrove. For more information on this, please see the Press Releases section on the Media Centre page, or Click Here.

Lord Montague plants Princeton Elm

Princeton Elms are now available in the U.K. for the first time in very limited numbers.

For current availability, sizes and pricing please go to our online store. Princeton elms are the perfect selection for gardens, arboreta, parks, estates and street plantings. Anywhere a large, graceful and
long-lived specimen tree would enhance the beauty of the landscape is the perfect spot for a
Princeton elm!

Originally Selected in 1920 for Superior Ornamental and Horticultural Features

Now available in the U.K. for the first time. The Princeton elm (Ulmus americana 'Princeton') was originally selected in 1920 for its superior horticultural and ornamental features including large leathery foliage, the classic elm shape and observed resistance to maladies known at that time to affect elms. Roads lined with Princeton elms planted in 1932 remain in perfect and picturesque condition today over 70 years later with a survival rate of over 95% from ALL causes. Considering the fact that all of the surrounding streets in the borough of Princeton planted with seedling American elms and presumably other elm varieties were virtually wiped out by Dutch elm disease, the vigorous survival of these Princeton elms is nothing short of remarkable. It is important to note that the 1932 plantings of Princeton elms occurred over a decade prior to the introduction of Dutch elm disease into the Princeton area.

		Published results from a recently concluded two decades long research study conducted by Ohio State University show that trees grown from cuttings on their own root average 56% greater caliper and canopy volume than trees grafted onto seedling rootstock. Since most who plant large trees do so with the hopes that the tree may live for centuries into the future, elms grown on their own root represent the best hope.
Princeton Elm from top to bottom.

Why are elms grown on their own roots superior?

One of the main reasons so many millions of mature elms were wiped out by Dutch elm disease was that the disease was passed from tree to tree via their intertwined roots, which were just as susceptible to the fungus as the tops of the trees. A beetle carrying the fungus would infect one tree and before long a whole area of elms would be decimated via root-to-root transmission.

Until recently, it was only possible to reliably produce these elms by grafting their cuttings onto seedling elm rootstock that had no resistance to DED. Since this then left the trees vulnerable some growers began grafting onto Siberian elm (Ulmus pumila) rootstock. Despite the fact that, as noted horticultural writer Dr Michael Dirr opined, Siberian elm is 'one of, if not the, worlds worst trees', the real problem with using its rootstock is the long term compatibility of a large elm such as Princeton having roots from a tree that attains only half of its mature size. While this incompatibility may not become evident for decades, eventually the large tree will suffer from an inadequate root system. Graft unions are also quite often entry points for disease and pests.

In the early 1990's, the USDA National Arboretum tested several selected varieties, seedlings and hybrids of elms by injecting them with artificially severe doses of the most aggressive strain of Dutch elm disease. In the summer of 2001 the follow-up data to those tests was published. The Princeton elm had a 96% survival rate from the injections. No other variety of DED susceptible, large-leafed elm can boast the combination of disease resistance and longevity in the landscape possessed by the Princeton elm.
		Planted in 1932, this avenue of Princeton Elms is now over 70' tall and still in perfect condition.