Dr. Michael A. Dirr Offering Future Tree Selections

Syringa reticulata / Syringa pekinensis-LilacGreat cold hardy, small flowering trees with new cultivars coming at faster rate than I caneffectively monitor. ‘Chantilly Lace’, ‘China Gold’, ‘Golden Eclipse’, ‘Ivory Silk’ (SUPPLIER:J. Frank Schmidt & Son and Loma Vista Nursery, Inc. I Photos Courtesy of Loma Vista Nursery,Inc.), ‘Regent’, Signature (‘Sigzam’), Snow Cap (‘Elliott’), Snow Dance, ‘Summer Snow’from S. reticulata; Beijing Gold ® , (SUPPLIER: J. Frank Schmidt & Son I No Photo) China Snow ® ,Copper Curls, Summer Charm ® (SUPPLIER: J. Frank Schmidt & Son and Loma Vista Nursery,Inc. I No Photo) from S. pekinensis.Tilia-LindenAlmost gave up on lindens (too many T. cordata clones) but continue to witness wonderful specimens. Summer Sprite (SUPPLIER: J.Frank Schmidt & Son I Photos Courtesy of J. Frank Schmidt & Son), from Halka is a compact, broad-pyramidal form that performs well inZone 7; was 15’ high at Schmidt’s; ‘Corinthian’ and ‘Olympic’ continue to impress for habit and foliage. Tilia kiusianum is a small-staturedlinden with elegant foliage andexfoliating bark. This could bea sleeper. Also, Tilia americanaranges from Maine to Florida andoffers numerous opportunitiesfor superior selections. Anenterprising breeder could makehay with a Tilia hybridizationprogram.Ulmus-ElmUsed to be simply the mention of the name was akin to swearing. Doesnot appear the situation today with U. americana being reestablished,especially the selections ‘Princeton’, ‘Jefferson’, ‘Valley Forge’ and ‘NewHarmony’; also newer selections ‘Creole Queen’ from Louisiana andPrairie Expedition (‘Lewis and Clark’) from North Dakota. Hybrids(largely) from Morton Arboretum have not impressed with exception ofTriumph; Accolade, Commendation, and Vanguard are wild andwoolly. New selection, Emerald Sunshine, (SUPPLIER: J. Frank Schmidt& Son I Photos Courtesy of J. Frank Schmidt & Son) from U. japonica(U. propinqua), with a thick leaf and heavy pubescence on lower surfacethat minimizes elm leaf beetle damage. New Ulmus parvifolia ‘Small Frye’with broad-rounded head, dark green foliage, exfoliating bark, and smallstature; will be introduced by Plant Introductions, Inc.Dr. George Ware, Morton Arboretum, continues the elm evaluation work with 12 Chinese species including U. gaussenii (Anhui), U.bergmanniana (Bergman), U. chenmoui (Chenmou), U. castaneifolia (Chestnut), U. propinqua var. suberosa (Corkbark), U. davidianavar. mandshurica (Father David), U. glaucescens var. lasiocarpa (Gansu), U. harbinensis (Harbin), U. lamellosa (Hebei), U. prunifolia(Plum-leaved), U. taihangshanensis (Taihang Mountain) and U. microcarpa (Tibetan). Dr. Ware is intrigued by the Anhui elm as it thrivesin streamside habitats and thus may tolerate low oxygen levels.Certainly, there are additional genera that can be manipulated to produce improved urban and suburban trees. The major liner producersare searching for cultivars that can be sold in large numbers. Think adaptability and long-term performance when assessing whether aselection has any hope in the market. n www.wnla.org