Answer: Lilacs can be host to a couple of problems, and the first signs can be yellowing of leaves. Lilac tip blight will eventually turn the leaf tips brown. It's a fungal disease that is rather self-limiting. You can rake the leaves up at the end of the season to keep the fungal spores from reinfecting the shrub over the winter months. Lilac's can also suffer from leafminer damage. Leafminers are little worms which feed on the tissues between the upper and lower surfaces of leaves. Pick off and destroy infested leaves. Lilacs prefer soil that's slightly alkaline. Here in the Pacific Northwest the soil is acidic. You can help mellow the soil by applying lime this fall over the root zone of your lilac. Finally, lilac's leaf out fairly early in the season, which means they lose their leaves earlier than many other plants, so the yellowing tips might just indicate a natural senescence. Make sure your lilac has enough moisture (supply one-inch of water per week if there's no natural rainfall)and watch for further developments.
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