Why Do My Sweet Alyssum Keep Dying?

Why Do My Sweet Alyssum Keep Dying?

“Every year I try planting alyssum and within 48 hours of planting its dead? I’ve tried many different things but can’t seem to get it to work at this house.  I’ve grown it in other beds and borders just not working here … any thoughts?” Question from Kyla of Oakbank, Manitoba, Canada

Answer: Sweet alyssum (Lobularia maritima) is a common bedding plant that originates as a seaside plant from the coasts of the Mediterranean and Europe. It can withstand the cool temperatures of spring as well as the heat and drought of summer, but there are several things that are certain to kill it early in the season. Here are the top four possibilities.

  1. Below-freezing temperatures – Spring-purchased alyssum plants have been greenhouse-grown and are more tender than average and sensitive to temperatures near or below freezing. Once well-established and growing, they can take light frost.
  2. Poor drainage – Maritime plants like alyssum are adapted to very sharply drained soils. They will grow well in organic-rich soils if they are porous and have very good drainage. Pot-grown specimens require a mix with good drainage, such as Black Gold All Purpose Potting Mix. The containers also need to drain well through holes at the bottom.
  3. Cold, wet weather – Cold, wet weather can induce fungal disease and subsequent root and crown rot.
  4. Poor Irrigation before establishment – Newly planted annuals need even moisture and good care while they are becoming established. If they are not properly watered from the start, they can dry out and die quickly. Those planted as small plugs are especially susceptible to drying because they have tiny root systems.

If your plants are subjected to one or more of these stresses shortly after planting, death can occur. But, below-freezing cold is the fastest killer. I hope that these tips help!

Happy gardening,

Jessie Keith

Black Gold Horticulturist


Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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