Question From: D. R - Manassas, Virginia, United States
Q: I saw your article about American elm and have been reading elsewhere also about different varieties. My daughter has decided to do a school science project on elm seed germination, so I am trying to locate seeds of DED-resistant varieties "New Harmony", "Princeton" and/or "Frontier". Do you know of any sources? Thanks.
Today most elms are grown from cuttings as explained by the following clip from Wikipedia.
Elm propagation methods vary according to elm type and location, and the plantsman needs. Native species may be propagated by seed. In their natural setting native species, such as wych elm and European White Elm in central and northern Europe and Field Elm in southern Europe, set viable seed in favourable seasons. Optimal conditions occur after a late warm spring. After pollination, seeds of spring-flowering elms ripen and fall at the start of summer (June); they remain viable for only a few days. They are planted in sandy potting-soil at a depth of one centimetre, and germinate in three weeks. Slow-germinating American Elm will remain dormant until the second season. Seeds from autumn-flowering elms ripen in the Fall and germinate in the spring. Since elms may hybridize within and between species, seed-propagation entails a hybridisation risk. In unfavourable seasons elm seeds are usually sterile. Elms outside their natural range, such as *Ulmus procera * in England, and elms unable to pollinate because pollen-sources are genetically identical, are sterile and are propagated by vegetative reproduction . Vegetative reproduction is also used to produce genetically identical elms (clones). Methods include the winter transplanting of root-suckers ; taking hardwood cuttings from vigorous one-year-old shoots in late winter, taking root-cuttings in early spring; taking softwood cuttings in early summer; grafting ; layering ; and micropropagation . A bottom heat of 18 degrees and humid conditions are maintained for hard- and softwood cuttings. The transplanting of root-suckers remains the easiest and commonest propagation-method for European Field Elm and its hybrids. For 'specimen' urban elms, grafting to wych-elm root-stock may be used to eliminate suckering or to ensure stronger root-growth. The mutant-elm cultivars are usually grafted, the weeping elms 'Camperdown' and 'Horizontalis' at 2-3 m, the dwarf cultivars 'Nana' and 'Jacqueline Hillier' at ground level. Since the Siberian Elm is drought-tolerant, in dry countries new varieties of elm are often root-grafted on this species.
However, a google search came up with a company called Tree in a Box and they sell tree seeds. 1-800-343-2313. I would contact them. Best And Happy Yardening, Nancy