The New Hampshire state flower, lilac (Syringa), thrives in Maine's cold-winter, warm-summer climate. Several white varieties of this showy, fragrant shrub are available, though some will only tolerate Southern Maine's climate. Maine is located in USDA Plant Hardiness Zones 3 to 5a, and Portland, the biggest city in the state, is located in zone 5a. Plant lilacs, which bloom in May, in full sun to part shade, and provide regular water.
Chinese lilac (S. chinensis) is a hybrid between the common lilac (S. vulgaris) and the Persian lilac (S. persica). This variety can grow to 15 feet and has fine-textured green foliage with open clusters of fragrant flowers. Hardy to zone 5, Chinese lilac should be planted in Southern Maine. "Alba" cultivar has white flowers.
S. hyacinthiflora is an early-blooming lilac that is a cross between the common lilac and S. oblata, a Chinese variety not easily found in the U.S. This variety is extremely fragrant and is suitable to plant throughout Maine. The "Mount Baker" and "White Hyacinth" cultivars produce a single white bloom, while "Gertrude Leslie" produces a double white bloom.
The common lilac is the most well-known and fragrant variety of the genus and will thrive throughout Maine. This variety can grow to 20 feet high and wide. Foliage is round and dark green. Common lilacs bloom in early spring, and flower clusters may reach 10 inches long. The "Alba" cultivar produces white blooms while "Krasavista Moskvy" has pink buds that open to white flowers.