July 1, 2011

A Lesson

On the first of every month Joene sponsors GOOPs --- Gardening oops --- those mistakes we all make and are willing to confess to.  I've posted many of mine.

This month I have an oops to confess, but it is also something others can learn from, as in "Don't Do That".

Don't do what I did to a newly planted groundcover.  I suffocated it.

The beautiful glossy leaves on this groundcover belong to Salix yezoalpina.  Salix is the willow family, and yes, it is a willow, but an unusual, low growing, spreading willow, also called dwarf pussywillow.
It has glossy leaves that have a fuzzy white underside that is interesting.  One plant will reach out to cover about four or five feet of ground, staying well behaved.

Although it spreads along the ground, it does have the characteristic pussy willow catkins, as this photo from empressjoan at Dave's Garden shows (mine was too new to bloom yet):

When I first got this plant, and it was still in its pot waiting to be planted, it developed a bad case of aphids.  Normally I can live with aphids on my plants, I use the hose to spray them off, or wait for the birds or ladybugs to make lunch out of them.

But this pot was heavily infested, and since it was still in a flimsy plastic pot, a strong jet spray from the hose would have sent it flying.  So I reached for the spray bottle of horticultural oil.  That gets rid of aphids and other soft bodied bugs by smothering them in a coat of oil.  It completely took care of the problem.

It's safe.  It is not a chemical pesticide, it is simply a viscous mineral or vegetable oil with an emulsifying agent to help it stick.

There is a heavy version that you use in winter when plants have no leaves, and it coats the larvae on stems and bark.  That's called dormant oil, but it is too heavy to use in summer.  It smothers everything, including the openings on foliage that the plants need to respire.  So you only use it in winter when there are no leaves out.

The lighter oil, called summer oil, or superior oil, can be sprayed on foliage, and that's what I used. 

The lighter hort oils still block the openings on the leaves somewhat, but the plant is not really affected unless temperatures get into the 90s and hot sun stresses the respiration of the leaves.

Guess what our temperatures were.  Guess how much sun these plants got when I finally put them in the ground.

We had a hot sunny heat wave in June, with two days in the mid 90s.  As a new transplant I watered it well. The willow was lovely and green for a week or so after its bath in hort oil, but when the temps soared and the sun beat down and the leaves could not respire all that extra watering, it gasped, suffocating.  You see the results. 

Do not ever use hort oil on plants that are in full leaf if it is going to be very hot and sunny. Do not water them heavily, increasing their desperate attempt to move water through the clogged leaves.

Do not overspray and saturate everything in the belief that more is better.

I cut off the dead leaves, and new foliage is beginning to grow out now.  From here on, I promise not to spray hort oil on leaves, water heavily, and set any plant out in summer sun and temps ever again.  I learned a lesson.


  1. You did learn a valuable lesson. This is a call about which I get often. So many people do what you have done and apply the oil at the wrong time. I think you cooked it a bit too.

  2. Laurrie, A good lesson we all need reinforced occasionally. It looks like your little plant will eventually recover. By next spring, I'm sure it will be fine. I've never heard of that plant before. I love unusual grondcover plants. Did you buy it locally?

  3. Laurrie, this is exactly the type of sharing I hope my GOOPs meme will entice. Thanks so much for offering this valuable lesson to your readers and mine.

    Even seasoned gardeners need occasional reminders to use horticultural oil with care.

  4. Donna, I did cook this new transplant! But it will recover and survive my ignorant mistake.

    Debbie, I got this groundcover willow at Farmington Valley Nursery. I know it is not near you, but it would be worth a trip up here... Kevin Wilcox is a fascinating horticulturalist with unusual woody plants (few perennials). He propagates and grows everything he sells right here in CT.

    Joene, it makes me happy that my complete ignorance, foolishness and abuse of plants is helpful to someone : )

  5. How sad, it was such a healthy looking plant. Stick to the hose dousing.

  6. Just call me the GOOPS queen. I don't think there's a week goes by when I'm not learning from my mistakes out in the garden, but I think that's what helps keep us going. We do eventually learn from it all! I rather like the way you share your mistakes with us all, so we can all learn such valuable lessons.

  7. Awww, poor thing. At least it survived and you learned something. That's what goops are for. :)

  8. Lesson learned! Fortunately, like children, our gardens are usually resilient! Have a happy 4th Laurrie!

  9. It's a shame about the plant but these GOOPS are great for us to learn from. (not just yours, the meme in general!) I've never heard of summer hort oil before and if I found it I never would have known how to use it properly.

  10. Oh, Laurie, I'm glad the roots are good and new leaves are coming out! it is a beautiful plant. I'm not so familiar with it, but you have made me want one. I promise to go easy on the horticultural oil!

  11. O gosh! It's fried, isn't it?! I hope it comes out of it ok. I will definitely look up the GOOPS host! It's always easier to learn from someone else's mistakes...I have made plenty of my own!

  12. Lisa, I am definitely sticking to the hose for spraying aphids from now on.

    Bernie, we do learn, it's all trial and error, and a little bit of seeing what others have screwed up!

    Garden Ms. S, it did survive, despite me. Actually the willow is growing well now.

    Cat, I'm not even going to think of the mistakes I made with my children... who turned out well in spite of me.

    Marguerite, summer hort oil has its place, just not the way I applied it.

    Deborah, I had never seen this willow either, but it caught my eye at the nursery, and he had a mature one growing in the soil in a bed... a very nice spreader.

    Sissy, thank goodness for everyone's mistakes... we learn! I loved your bird story at the garden center.

  13. Interesting, both the lesson and the plant. I hadn't seen this plant before. I'll have to look it up and see if it would like the Southeast.

  14. I'm the GOOP queen!! I have a little "that was stupid!' alarm that goes off in my head a lot more than I'd like to admit. I'm going to have to check out Jolene's blog! I have a pot of chenille plant, an annual that has similar flowers to your groundcover. It was one of the few flowers to survive last years Mite Infestation from Hell. Glad your plant is recovering. Watch out for it when it gets dark. It might seek revenge!!


Sorry about requiring code verification -- I experimented with turning it off to make commenting easier, and I got too much spam. Thanks for taking the time to comment, and to type in silly codes. I appreciate hearing from you.