Common lilac

Year-round

Common lilac is a dependable shrub for the Albuquerque area. It is not native to New Mexico, its origin is southeastern Europe, but it does well here because it tolerates the region's alkaline soil and gets the cold winter chill it needs to set flower buds each year.

• Give it full sun, at least six hours a day, for the best bloom.
• It tolerates a wide soil pH range, including the alkaline soil common around Albuquerque, as long as drainage is decent.
• It is not on the ASPCA's list of plants toxic to dogs, cats, or horses. A different plant sometimes also called Persian lilac, Melia azedarach, is a separate and toxic species, so it is worth double checking which one is actually in your yard.
• It blooms on the previous year's wood, so pruning needs to happen right after flowering, not in fall or winter.
• Skip heavy nitrogen fertilizer. A light application of a balanced fertilizer in late winter is enough.

Summer

Albuquerque summers are hot and dry with a monsoon push of rain in July and August. Once established, common lilac handles this well, but it still wants regular deep water rather than frequent shallow sprinkles.

• Water if the shrub has gotten less than about an inch of rain in a week, and water deeply rather than a quick daily splash.
• Keep mulch a few inches deep over the root zone to buffer soil temperature and hold moisture in the heat.
• Do not fertilize with a nitrogen heavy product now. It pushes soft new growth instead of next year's flower buds.
• Avoid pruning in summer. Any cuts now remove the flower buds the shrub is already setting for next spring.

Fall

Fall in Albuquerque brings cooling days, with the first freeze usually landing anywhere from late October into November depending on the year and your spot in the metro. This is a wind down season for common lilac, not a pruning or feeding season.

• Skip pruning now. Lilac sets next spring's flower buds on this year's wood, so a fall cut trades away next year's bloom.
• Rake and remove fallen leaves from around the base to keep the bed tidy heading into winter.
• Taper off watering as growth slows, but do not let the root zone go bone dry heading into winter.
• Hold off on fertilizer. A fall feeding can push tender new growth that will not have time to harden off before frost.

Clearing fallen leaves from the bed keeps the front yard looking tended even as the shrub goes dormant.

Winter

Albuquerque winters are cold enough to give common lilac the chill it needs, but they are also dry, so established shrubs still need occasional deep watering through the season.

• Water about every 45 to 60 days from December through March, soaking to a depth of roughly 18 to 24 inches each time, since a few inches of snow is not enough water on its own.
• Pick a mild, sunny day above freezing to water rather than watering right before or during a hard freeze.
• Leave pruning alone this time of year. The flower buds for next spring are already set, and winter cuts remove them.
• A newly planted lilac, less than a year in the ground, will need water more often than an established one.

The bare winter branch structure stays neat on its own, so there is little upkeep needed to keep the front yard tidy through winter.

Spring

Spring is bloom season and the only real pruning window for common lilac in the Albuquerque area. The average last freeze lands anywhere from early to late April depending on where in the metro you are, so an unusually late cold snap can still nip open flowers some years.

• Prune right after the flowers fade, within a few weeks, since next year's buds start forming soon after on the new wood.
• Remove up to about a third of the oldest, thickest canes at ground level so the shrub keeps renewing itself.
• Deadhead spent flower clusters before they set seed so the plant puts its energy into next year's buds instead.
• Water deeply as new growth picks up, and keep mulch refreshed to hold soil moisture through the dry spring wind.

A quick deadhead and shape up right after bloom keeps the shrub looking neat from the street for the rest of the growing season.