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Lilac

May 14, 2016

QuestionI live in central Arkansas and have two lilacs that have not bloomed since they were planted several years ago. I dug up small plants surrounding a large shrub in my parent's yard in north central Arkansas and put them in pots until they had grown and developed a good root system. It seems as if they get enough sun. What could be the problem?

 

Answer

Lilacs can be a bit finicky to grow in the south. They prefer a mild, cool summer which we typically do not have.  Last year was pretty mild, until September hit and then it was so dry.  The key to success with lilacs in the south is to give them full morning sun, and total shade in the afternoon.  Add a bit of lime to the planting soil since they like a bit more alkalinity.  Water them when it is dry and fertilize once a year in the spring after they should have bloomed.  Try not to do much pruning or moving.  I have seen some great lilacs this spring, but more so in the northern tier of our state than in the southern half. 


 

August 2012

QuestionI have a lilac bush that does not get full sun, but it does bloom occasionally. It is getting fairly large. When should I prune it?

 

AnswerLilac plants set their flower buds in late summer to early fall and bloom in the spring. They should only be pruned as needed, immediately after bloom in the spring. It is way too late to prune them this year. Many of our plants had an expedited spring and have already set their flower buds for next year. Pruning now would definitely impact the bloom ability of this plant. For now, just keep it watered and do any needed pruning next year as soon as the flowers fade.


April 2012

QuestionWe recently moved to central Arkansas from Missouri and have tried to grow lilac bushes but we cannot keep them thru the winter. It seems in late summer the leaves get a blight, which then turns the leaf tips brown. One bush died and we have replaced it hoping we will have better luck. Have you got any suggestions as to what we should do?

 

AnswerAlthough numerous cultivars of lilacs (Syringa vulgaris) are on the market claiming heat tolerance, they often do not thrive in central and southern Arkansas as well as in more northern climates. Common lilacs struggle during periods of high heat and humidity, which can lead to problems with powdery mildew. ‘Miss Kim’ is a cultivar of Syringa patula and is more tolerant of heat, but it does not produce the large, showy flowers of the common lilac. They are pretty and fragrant, but smaller. Some of the Descanso hybrids were developed in Southern California and would be worth trying in our climate. They include the white ‘Angel White’, blue ‘Blue Boy’ and the pink ‘California Rose’. For all lilacs amend the soil with lime because they like a more alkaline soil than we typically have. Give them full morning sun and afternoon shade. There are quite a few gardeners who get fragrant blooms on their lilacs annually, but they don’t compare to those grown up north.


April 2008

QuestionWe recently moved back to Cabot, Arkansas from St Louis Mo and have tried to grow lilac bushes but we can not keep them thru the winter. It seems in late summer the leaves get a blight, turning the leaf tips brown. One bush died and we have replaced it hoping we will have better luck. Have you got any suggestions as to what we should do?

 

AnswerWinter is usually not the problem with lilacs—usually summer is more of an issue. Lilac plants are quite cold tolerant, but struggle in heat and humidity. Make sure the site you are planting in has good drainage, as winter drainage is usually worse than during the growing season. Make sure that the plants are not planted too deep in the ground and that no fertilizer is added to the planting soil. Choose a location with full morning sun and afternoon shade. Cut the root ball at planting to ensure that the roots will spread out. Plant at the same depth or slightly shallower than the depth they are in the container. Water when dry, mulch and they should grow—albeit not as well as in St. Louis. Lilacs are susceptible to powdery mildew with our Arkansas humidity, but rarely would that kill a plant in one season.


April 2007

QuestionMy lilacs bloomed as usual, but I have noted in the last few years that the color is not there like in the past. I do not fertilize-should I? They still smell!

 

AnswerWhile it is a proven fact that you can change the color of the hydrangea blossom by changing the pH of the soil, which is not true of lilacs. However color intensity of many plants can be altered by low fertility and a change in pH. Lilacs prefer a slightly alkaline soil—and many of the soils in Arkansas tend to be acidic. Take a soil sample from around your lilac and see if changes need to be made. Liming is an easy way to raise the pH, but it doesn’t change it overnight. A light application once a year after blooming is also beneficial. Keep up with watering needs, and enjoy your blooms each spring.


April 2009

QuestionMy lilacs were really beautiful this year and I want to encourage them to be even more beautiful next year. Are lilacs supposed to be pruned and if so, how and when should it be done? I would appreciate your assistance very much.

 

AnswerLilacs should be prettier than normal this year, because we had a cooler than normal summer last year. Lilacs thrive in cool seasons, and can struggle when we have a hot, humid summer. They set their flower buds at the end of summer into early fall, so weather conditions then can play a part in how well they do the following spring. While you can’t control the weather, you can keep them happy with regular water when dry, and a slow release fertilizer now. They also like a more alkaline environment, so add a little lime around the plants every few years. If the plants fit their location, pruning is not needed.


June 2009

QuestionI live in Conway. Is it too early for Lilacs to bloom? I have three young ones that bloomed last year but I don't remember what month.

 

AnswerI would say it is getting a bit late for lilacs to bloom. Typically they flower in April and May in Arkansas.


September 2006

QuestionWhen is the best time to prune lilacs?

 

AnswerLilacs are spring blooming plants, so are best pruned immediately following bloom in the spring. Don't do any pruning now, or what flowers they might have will be cut off. They are setting or have set flowers now. We have enough problems getting lilacs to bloom in our heat anyway.


 

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