Plant of the Week: Allysum

I used to dislike allysum.  We always started off on the right foot, allysum and I, with her sweet blooms cheerily spreading in the spring.  But then the heat of summer would come along and the low-growing annual would almost disapear with only a few crispy leaves left to show.  To me, our growing season is just too short to mess around with finicky annuals!  Thankfully a volunteer introduced allysum to one of the flowerbeds in the Display Gardens a few years ago and I have had a change of heart.

Genus:  Lobularia

This annual’s common name comes from the genus it was formerly classified under.  Another very similar genus, Aurinia, also used to be classified under Allysum.

Family:  Brassicaceae

This family also includes broccoli, cabbage, cauliflower, turnip, radish and horseradish.

In the Display Gardens, the allysum reseeds each season and blooms all summer long.  The delicate white flowers bloom so thick that they create a carpet effect along the flowerbed’s border.  This thickness also pushes out any weeds – wich I especially love!

Often allysum does not thrive like this all season in Iowa – so what’s the trick in the Display Gardens?  In this case it might be a bit of shading by neighboring plants that benefits the allysum.  The annual likes full sun and is drought tolerant, but in warmer summer climates like ours, allysum likes to be kept cooler (like the rest of us!).  I have also heard that the white blooming allysum is more tolerant than the purple and pink hues.  I don’t have research to back that up, but do know that a community garden last year (several yards away) included purple allysum that did not bloom mid summer.  The purple allysum also did not have any shade.

Just when you think you know a plant, it will turn around and do the complete opposite on you.  That’s the great part about gardening – there is always more to learn!  Do you have an annual or perennial that you’ve tried to grow but it never grows for you?  Do a little  asking around – find someone who grows it well and see if you can mimic those conditions in your garden.

See you in the gardens.

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