flowers if unpruned. If pruned, the plant responds by producing fast-growing young vegetative growth with no flowers, in an attempt to restore the removed branches. Lilac bushes can be prone to powdery mildew disease. The wood of lilac is close-grained, diffuse-porous, extremely hard and one of the densest in Europe. The sapwood is typically cream-coloured and the heartwood has various shades of brown and purple. Lilac wood has traditionally been used for engraving, musical instruments, knife handles, etc. When drying, the wood has a tendency to encurve into a twisted form and to split into narrow sticks. Symbolism Lilacs are often considered to symbolize first love. In Greece, Macedonia, Lebanon, and Cyprus, the lilac is strongly associated with Easter time because it flowers around that time; it is consequently called paschalia. In the poem When Lilacs Last in the Dooryard Bloom'd, by Walt Whitman, lilacs are a reference to Abraham Lincoln. Syringa vulgaris is the state flower of New Hampshire, because it "is symbolic of that hardy character of the men and women of the Granite State." Festivals Several locations in North America hold annual Lilac Festivals, including: The Arnold Arboretum in Boston, Massachusetts, which celebrates "Lilac Sunday" every May. The Arboretum shows off its collection of over 422 lilac plants, of 194 different varieties. Lilac Sunday is the only day of the year when picnicking is allowed on the grounds of the Arboretum. Lombard, Illinois, called the "Lilac Village", which has an annual lilac festival and parade in May. The village also contains Lilacia Park, a garden with over 200 varieties of lilacs, as well as over 50 kinds of tulips. Mackinac Island, in Michigan, which celebrates a weeklong lilac festival and lilac parade each June. Rochester, New York, which has held its Lilac Festival since 1898, hosts the longest-running festival in North America. Held in Highland Park, this celebration features 1,200 shrubs, representing over 500 varieties, many of which were developed in Rochester. It is the largest collection of varieties at any single place. The Royal Botanical Gardens near Hamilton, Ontario, which holds its Lilac Celebration each May. Spokane, Washington, known as the "Lilac City", which holds an annual lilac festival and lilac parade. Franktown, Ontario, Canada, holds an annual festival. Species Species and subspecies currently accepted as of July 2016: Syringa emodi Wall. ex Royle – Himalayan lilac - northern India, Pakistan, Tibet, Nepal Syringa josikaea J.Jacq.