This classic lilac… Designers use these trees … As the tree … This is the last Lilac to bloom, and it's a must-have in your landscape. This tree has an oval-shaped canopy … Extend the lilac season to summer with species such as Littleleaf lilac (Syringa microphylla) and Japanese tree lilac (Syringa reticulata). The creamy white flowers are the last of the lilacs to bloom. These lilac shrubs do not only bloom … Young trees show an oval to pyramidal form. The Japanese lilac "Ivory Silk" tree grows to an average height of 25 feet, with an average width, or spread, of 15 feet, according to the University of Florida. It grows upright when young and becomes more spreading with age. Only prune this lilac right after the blooms are done, and be very careful not to give any high nitrogen fertilizer and yours will flower beautifully. The best thing about Japanese Lilac Trees (Syringa reticulata) is they start blooming at a time when all of the spring-flowering shrubs and trees are done blooming. With a pleasing form and compact size, "Ivory Silk" Japanese lilac reaches 20 to 30 feet in height at maturity and spreads 15 to 18 feet in width. If your space is limited and you cannot enjoy several lilac varieties, you may want to choose a reblooming lilac.