It's snowing once again so it's the perfect time to discuss lilacs. Oh to smell their perfume and watch their clusters of flowers sway in the breeze.
Lilacs are a personal favorite of mine (favorite of mine is a phrase you'll be reading frequently). At first I was tempted by the scent and the memories of spring they bring about. Then I was drawn in by the numerous flower colors they offer. But once I started meeting them at the garden center and planting them in my own yard I discovered their best quality: durability. Yes, the scent is nice, but their ability to thrive in just about any soil and survive dry summers is even more important.
This conclusion came about when I was working for a garden center. I'd always liked lilacs and found myself drawn in by the different types offered. Syringa vulgaris Sensation, was one of the first with its purple/white edged flowers. Then of course there was my attraction and subsequent disappointment with Syringa vulgaris Primrose. But one year, I discovered the lilac's tenacity and determination to survive. A landscaper had ordered a number of lilacs and never came to pick up his order. The poor plants were abandoned in the holding area; pushed further and further to the back as new orders were brought in. Then in August, I came across them while cleaning out plants and orders. The poor things had once been nicely dug and their roots/soil wrapped in burlap. Not any more. The burlap had rotted and the root balls were falling apart. The plants themselves, however, didn't seem to notice the indignity. I corralled them all and decided I would buy/rescue them and plant a hedge in the yard. At the time I wasn't sure how well they would do or if they'd even survive the experience.
Imagine my surprise when these plants not only survived, but thrived. There's a row of these lilacs planted next to a fairly busy road and sidewalk. It's a hot and dry exposure. The soil in this area has a heavy sand content (from back when the yard was a parking lot for horses and carriages) and receives sun all day long. The plants grow and flower with little in the way of attention and they always amaze me with their durability.
There are lilacs elsewhere in the yard, including an ancient stand of white common lilacs that came with the house. Exactly how old these lilacs are is unclear, but they perform well each season even with a Philadelphus attempting to take over. There had been others planted near it including more whites and a common purple, but this one is the only one to survive the competition from giant maples in the back yard.
Generally, lilacs enjoy sweet soil. Sprinkling some lime around them every couple years will be appreciated. Regular garden soil is fine for them although as I've discovered they tolerate all kinds of soil conditions. Sunlight is of utmost importance. Without it they will fail to flower and will readily contract the dreaded powdery mildew. The only other thing lilacs will not tolerate is wet feet, so planting them in a wet area is not advised. Not only will the plant fail to thrive, it will contract powdery mildew far more readily in damp locations. Fertilizing in the spring with a balanced fertilizer is fine (10-10-10 or 8-8-8 or any slow release fertilizer without a high first number).
Pruning lilacs is a bit more tricky, especially if you're worried about flowers. If not, then pruning in the early spring is best. An older plant can be cut back by 1/3 each year, with the removal of the largest thickest trunks, to promote lush new growth. If the lilac is especially overgrown, it can be cut back to the ground in the early spring with a reasonable chance for a full recovery. In order to preserve flower buds, prune the lilac right after it flowers. Remove any spent flower heads and trim out any branches that interfere with each other. Aim to open up the interior of the shrub to help with air flow and prevent powdery mildew. Of course, damaged or dead branches can be removed at any time.
Along with being especially tough, lilacs have few pests. Lilac borer can be a problem with some plants (for some reason, they like one of my Sensation lilacs). The insect is easily spotted because it leaves large exit holes in the trunk of the plant. Most lilacs will survive the insect, but become weakened by repeated infestations. As for diseases, lilacs are prone to powdery mildew and dieback caused by fungus. The mildew is not usually life threatening to the plant. The dieback can be, however. The tips of the plant will wilt, blacken and die and slowly this death will work down into the plant. At first it appears that the plant is thirsty, yet this is brought about by too much water combined with a fungus called Verticillium. This is an easy thing to identify as when you cut back the drooping growth you'll notice a brown/purple ring inside the stem. Improving drainage around the plant or backing off on watering will help the plant recover. Trim out any infected branches. Most often I've seen this wilt occur when the plants are too close to an automatic sprinkler system or planted in an area where water collects (near down spouts for example).
So, you're interested in lilacs, which ones will you look for? My list starts off with a group of vulgaris cultivars. Katherine Havemeyer has a wonderful scent and lavender-pink flowers. Lucie Baltet is a personal favorite of mine. The flower clusters are smaller than on most lilacs, but the buds start off a coppery-pink color and then the flowers open pink. It's an unusual color, especially when seen with other lilacs. President Lincoln is a fantastic grower and has single blue flowers. It's one of the most prolific bloomers I have, out flowering others planted nearby. Sensation has purple flowers with a white edge, but almost no scent. Sensation tends to be a but rangy in its growth habits too, but I still enjoy it. Krasavitsa Moskvy or Beauty of Moscow is an excellent white. The buds are pinkish but open a creamy white. Last but not least is Monge. It has wine-red/purple flowers. Not the darkest purple I've seen, but certainly the most interesting. The growth habit has been more shrubby than the others and it tends to send up lots of sucker growth. This is fine, as I can dig up the youngsters and share them with fellow gardeners.
One other option, which isn't part of the Syringa vulgaris list above, would be Syringa chinensis. This shrubby lilac becomes as wide as high (about 8 feet or so) and throws off a tremendous number of flowers. They are smaller than on the vulgaris cultivars and the color is the commonly seen pink-lavender, but it is certainly a plant worth having.
There are also French hybrids, which flower later than the vulgaris cultivars. I'm not as familiar with these plants, as I prefer the "classic" lilacs. If you're looking to extend bloom time, these are excellent options.
Previously I'd mentioned Primrose. I have a love-hate relationship with this plant. On the one hand, I'd love to find a true yellow lilac. On the other hand, Primrose is often promoted as being yellow...but it really isn't. The buds start out a creamy yellow color but when the flowers open they open creamy white. Yes, if you put something white behind/near the flower it does have a yellowish cast...if you squint...and the light is just right. In my mind, the color is reminiscent of certain brands of vanilla ice cream. Certainly not worth going out of the way for.
So, with the snow falling steadily, and the lilacs out in the yard slumbering away one can think towards spring and scent and green.
Recommended Plant of the Day: Hydrangea quercifolia. An excellent hydrangea for shadier spots it produces large panicles of white flowers. The leaves are large and look like oak leaves--hence the common name "Oak Leaf Hydrangea." Now on most hydrangeas, the flowers are the best feature. This plant, however, offers up excellent fall foliage and interesting bark that peels off. Once cooler weather hits, the foliage turns various shades of yellow, rust, red, burgundy...all rich fall colors and all on the same plant. Some years the flowers will hold on for quite some time, turning a pinkish shade in the process, and still show when the foliage turns. There are various hybrids out there which are all worth trying, but the standard Oak Leaf is an excellent choice on its own. For more information visit: http://www.hydrangeashydrangeas.com/oakleaf.html
For more information on lilacs visit: http://www.arboretum.harvard.edu/plants/lilac_sunday.html
If you're looking for a source for lilacs I recommend: