Editor’s note: Arnold Arboretum has canceled this year’s Lilac Sunday due to severe weather threats. Modified events will be offered Saturday.
> 6 — Weeks that lilacs stay in bloom at the Arnold Arboretum, usually beginning in early May
> 281 — Acres in the Arboretum; lilacs take up about 0.6
> 1908 — Year the Arboretum held its first Lilac Day
> 49 — Maximum height in feet of a Japanese tree lilac (the oldest one at the Arboretum is 29.5 feet tall)
> 15,000 — Approximate number of plants the Arboretum cultivates
> 369 — Number of lilac plants in the Arboretum’s space, with 110 of them being the common lilac (Syringa vulgaris)
> 165 — Types of lilacs in the Arboretum’s collection
> 1872 — Year the Arnold Arboretum was founded, as the first public arboretum in North America
> 1876 — Year the Arboretum added a Japanese tree lilac, the first lilac plant acquired by the Arboretum (lilacs were already on the grounds given to Harvard by Benjamin Bussey)
> 43,000 — Number of people said to have attended Lilac Sunday in 1941, considered its peak year
> 1750 — Year the oldest living lilacs in North America are said to have been planted, in Portsmouth, New Hampshire
> 20 — Number of food trucks expected at this year’s Lilac Sunday, the only day of the year picnicking is allowed at the Arboretum
“May is lilac here in New England.” — Poet Amy Lowell, “Lilacs”
Sources: Arnold Arboretum; The Poetry FoundationSend comments to firstname.lastname@example.org. Follow us on Twitter @BostonGlobeMag.