Approximately twenty seven thousand different plants (27,000 taxa) make up the plant collection at Juniper Level Botanic Garden, and there was one plant that elicited a huge number of questions at the recently completed Spring Open Nursery and Garden Days. It probably helped that at 40′ tall it towered over the welcome tent (no it wasn’t a new mega-hosta), and that it was in bloom, and it is fragrant. The plant was the Chinese tree lilac, Syringa reticulata subsp. pekinensis. It is a true lilac, in the same genus as the common lilac, Syringa vulgaris. The tree lilac’s flowers are cream colored like every privet (Ligustrum) I’ve ever seen and its fragrance is very much like the fragrance of privet. You either like or despise its perfume and our visitors were about equally divided. Lilacs and privets are very closely related, enough so that historically, lilacs were propagated by grafting a lilac scion on a privet understock. With modern day advances in rooting techniques lilacs are now propagated as stem cuttings and are no longer grafted.
The tree lilac is very cold tolerant, succeeding even into zone 3. For this reason it is much more frequently grown in the upper Midwest where winters can be brutal. There is a second specimen of the tree lilac here at JLBG, the cultivar ‘Ivory Silk’. Butterflies and hummingbirds visit the flowers and as is typical of the olive family (Oleaceae) deer tend to leave it alone. I do need to add that Plant Delights Nursery’s focus is on winter hardy herbaceous perennials so tree lilac is not likely to ever be offered for sale.
We’ve had some good luck with a lilac in Chapel Hill. We’ve had it at least 4 years now and it continues to improve each year. Unfortunately, I’ve lost the tag on it, but it might be the Miss Kim variety. On the topic of plants that aren’t supposed to survive in the heat of the Southeast, have you ever experimented with the Roscoea species? We had good luck with Roscoea x beesiana last year, so I ordered additional varieties from a west coast nursery, but they attempted to persuade me that my attempts to grow them would be doomed to failure. I have a nice partially shaded hillside site for them that should get around any sun scorch problems. Any thoughts?