Guess what a couple of acres of Lilacs flowering at the same time smell like? If you can't guess, I can't describe it. I can say that on a warm day with the wind blowing a little bit, the perfume suffuses Fern Valley (just beyond the tall trees in the background). This amazing collection of plants is not a public display, but a research field that consists of the taxa assembled for use as germplasm, and selected results of experimental crosses. Visitors aren't actively encouraged, but the area is open and if you don't pick the flowers, and obey all the other rules you are welcome to walk through. (One of the most important rules is no parking on the grass. It may seem counterintuitive, but park on the road at the side of the road!) This is a visit you ought to make at least once! Most of the classic Lilac cultivars are happier farther north than here; summer heat, humidity and heavy soils combine to create an inhospitable climate In fact, I feel like I have a good grasp of how most things horticultural work, and I can't explain the existence of these plants; there is no other equivalent collection this far south.
Research is the primary mission of the National Arboretum and The National Arboretum is the primary institution for tree and shrub breeding in the United States. Although better know for its Crape Myrtle introductions, the Arboretum has released 3 lilac cultivars, 'Betsy Ross', 'Declaration', and 'Old Glory.' While 'Declaration' is better suited to a cooler climate, the other two do well in this area. Other lilacs that do well in the heat of USDA Zone 7 are 'Donald Wyman' and 'Miss Canada', Preston hybrids, or 'Pocahontas' (Syringa x hyacinthiflora), the easiest to grow fragrant purple lilac. If you do want to grow the traditional hybrids, it helps to have good soil, full sun, don't overwater (this may at least partially explain our wonderful plants), and prune out the oldest canes if (realistically, when) they become invaded by borers. The "off", by which I mean the least trafficked, back corner of your house, if it has enough sun, is a traditional site for a Lilac. You can look at it when it is nice and ignore it when it is defoliated by powdery mildew.