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

I’m planting a privacy hedge of Leyland Cypress – What do I need to know about it?

Cupressocyparis leylandii, or Leyland cypress, is a very popular and fast-growing plant. It gives instant privacy, but this point is both a positive and negative fact. They simply grow too big.

Pruning is essential in keeping the Leyland cypress in check, and this presents other problems. If not pruned correctly, you may end up with a thicket of dead branches, or the base of the plant will become bare. Unlike yew and laurel, Leyland cypress cannot be cut back into bare wood.

I don’t think anyone knows just how tall this cypress will grow (up to 120 feet probably), but if planted as a hedge, you will have to be very diligent with your pruning or they will get out of hand very quickly. From our experience, we would trim back stray branches at the start of the growing season in April. Then in mid-summer (around July), trim the sides again to encourage denser growth, leaving the leading shoot uncut until it’s reaches the desired height. After that, the top and sides will need to be trimmed up to three times a year and tapered from the top to the bottom. This program of diligent clipping is critical and unfortunately they cannot be kept to a particularly width and will get wider and wider over time.

Spacing recommendations vary from four to eight feet, depending on how much money you want to spend. Carrie suggests five-miles apart. It sounds like you’ve already planned on spacing them every five feet and this would be fine.

Some other points you may want to consider before planting Leyland cypress is it’s susceptibility to disease, and may not be long-lived because of this (maybe only 15-years). It’s also not very drought tolerant and wants good draining soil. Ask yourself if this hedge will block out your sun to areas of the yard that are used to having sun.

As you can tell from our comments, this plant would probably not be our choice as it requires long-term and regular maintenance. Carrie suggests using plants such yew, holly, or osmanthus as a mixed and informal hedge. Susan prefers a little more formality and would opt to prune these plants, although they wouldn’t require the same amount of effort as the Leyland cypress. Bob says he would use them as a short-term solution while more preferable plants are planted in front of the cypress and allowed to grow up at a slower rate, and then remove the cypress. It would worth the time and expense to invest in Irish yews.

What’s the deal with hellebores? Should the leaves be removed from all hellebores?


Remove the leaves of H. orientalis to the ground in January and February, being careful not to damage the stems of the emerging flowers. This is done to prevent disease from spreading and so you can see the flowers better. We usually leave the plant alone for the first two years.

H. niger is a true evergreen, so only remove the leaves that look bad.

H. argutifolius and H. foetidus have biennial stems that produce flowers in their second year. After they flower these stems can be cut to the ground and new shoots will have already emerged.
Note: When you cut the stems back don’t leave stubs, cut them to the ground.