Sex Change

Weigela middendorffiana flower color change

Did that get your attention?  It certainly does for the bees that pollinate Weigela middendorffiana.  They have learned to visit yellow flowers preferentially, as they contain the most nectar.  As the flowers age, they turn red, and one study noticed that bees visit the older, less nutritious flowers less frequently.  Floral color change after fertilization is not uncommon (Asters, Orchids, Fuchsias), but the color change is probably dependent on age, not bee-behavior, because the pollen tubes require several days to reach the ovaries.  If the flower dropped off right after pollination, the plant wouldn’t be able to reproduce!  Thanks again go to Dan Hinkley and the Miller Garden for introducing me to this unusual shrub.

Spiny Holly?

I live in Gig Harbor, WA (cold zone 7) and would like to plant a “spiny” leaved holly that can grow to at least 10′ in height & width as a yard parameter hedge. The soil is acidic and has full shade from the towering Douglas Firs on the property. I found the below info about Blue Holly. Can you let me know if this will work before I invest the time and monies please. Any specific species recommendations that do well in the wet Pacific Northwest?

Photo Credit Jim Ross One Tree Landscape

Ilex x meserveae ‘Blue Princess’ actually prefers full sun to partly sunny conditions.  Although it may reach a height of ten-feet, it does so at a slow pace and probably wouldn’t fit your needs.  We’d recommend the standard English holly, Ilex aquifolium, as a plant that could work for you.  It does well in shade, grows fast, and can be pruned into a hedge shape if you desire.

English holly has both male and female plants and bee pollinated, so you’ll want one male holly for each hedge.  As with any new plants holly would require appropriate watering for the first several years to get it well established.

Susan, Bob, and Carrie

Rooftop trumpet vines?

Dear Expert (Carrie, Bob or Susan)
We have a client who’s property is situated on the 16th floor with a rooftop garden in downtown Seattle. The terraced garden faces south and southeast. The 4 trumpet vines are each in their own containers that are 24″ square x 26″ deep along with Algerian Ivy, trailing Rosemary. They get full sun and some wind, but are up against a wall. The foliage growth appears normal and they’re working their way up the metal trellis support. They have not bloomed yet, nor do they seem to be developing any buds. They bloomed last year (their 1st year in that spot) just coming out of a #5 nursery pot. So I can’t imagine that it’s because they’re growing in containers now. The pruning I did this spring was very light so I can’t see how that may be to blame. I also fertilized them in spring with an organic 9-3-4 all purpose fertilizer. I can’t figure out why they haven’t bloomed and hope you can.

Dear Cheryl,

Thank you for your question on trumpet vines, (Capsis radicans).  An American native, this vine really likes warm weather and with the exception of several days we really didn’t even have summer this year.  Also, some say it takes several years for the trumpet vine to flower but since it flowered last year this is probably not the problem.

This size of your container sounds fine, and your pruning technique was probably okay. The trumpet vine blooms on new wood, but it’s best not to cut it back too severely in the winter.

We’d recommend fertilizing your container plants more often, at least every two weeks if not weekly.  Miracle Grow would be an easy product to use.

Let us know how this works (next year).

Susan, Bob, and Carrie


I would like to plant some beesia at the top of a shady ravine.  I am concerned about the moisture level, though.  The area is dry shade, although I could run a line from my drip system along there.  Even though  I’ve read that beesia prefers moist soil, can it do OK with drier conditions? In this area I am trying to replace very established ivy.  If the beesia won’t work, what would you suggest?  Thanks so much!

Epimedium x versicolor 'Neosulphureum'

Epimedium x versicolor ‘Neosulphureum’

We love beesia!  Unfortunately, it wouldn’t be happy with the site you’ve described.  Beesia is an excellent ground cover for shady to part-shady, and consistently moist conditions.  I’m also curious if you’re able to remove all of the ivy.  I would put this at the top of the list, as ivy will pop back up if you haven’t gotten rid of every bit of it, and overwhelm almost any ground cover.

    Here are some suggestions of plants that would be appropriate for a dry shady site:

  • Privot honeysuckle, Lonicera pileata, is an evergreen boxwood-like foliage with a slow spreading habit, and makes a good bank-covering ground cover in part shade.
  • The woodrush, Luzula sylvayica is used as an ornamental ground cover for shady areas. It is best when planted in drifts.
  • Euphorbia amygdaloides var. robbiae also does well in dry shade, after it’s established.
  • It sounds like a site that would be appropriate for native plants such as Oregon grape, Mahonia repens, combined with sword ferns, Polystichum munitum.
  • The sedge, Carex ‘Ice Dance’ makes a nice ground cover in the shade garden, although will look it’s best if kept from average to moist conditions.
  • Evergreen epimediums are great woodland plants and are perfect for dry, shady spots. Epimedium ‘Enchantress’, E. x versicolor ‘Neosulphureum’ and ‘Sulphureum’ are among a few of the evergreen ones.

What is this?

The plant you’re inquiring about is Cardamine trifolia, commonly know as lady’s smock or 3-leaved cuckooflower. This is an attractive, well-behaved evergreen ground cover, about six-inches tall and covering up to twenty-four inches across. The dark green leaves with a purple reverse are three-parted. The white flowers are borne in early spring. Flowering is brief and they rarely set seed.

Cardamine trifolia prefers shade to part shade, but will tolerate sun if kept moist, and likes humus-rich soil. It’s a good companion plant for many plants in the spring and shade garden and especially looks good under Lace Leaf Japanese maples as there are few plants that like these conditions.
Photo: Thistledown Farm