Answer: The blooms on a lilac would naturally fade and turn brown within a fairly short time. The blooms only last for a week or two, depending on the weather. Hot weather makes them fade more quickly. Allowing the roots to dry out will also cause them to fade more quickly than they might. Trim away the faded blooms and make sure the soil is moist (but not soggy) around the root zone. Also, several inches of organic mulch such as shredded bark can help keep the soil moist and cool.
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