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Gardening Answers Knowledgebase

Plant Answer Line Question

Keywords: Verbascum, Annuals and biennials

I would like to know a little more about Verbascums. Are they a biennial? Will they reseed themselves? How long a period will they bloom. How tall can they become? Are they invasive? Thank you for you help! I have had very little experience with annuals and biennials.


Verbascum includes 360 species, most of which are biennials, with a few annuals, perennials, and small shrubs, some of which are evergreen or semi-evergreen. The flowers grow on tall upright stems, and while individual flowers are shortlived, there are many of them and they bloom over a long period of time (summer into early fall, in most Seattle gardens).

In my own experience, they can reseed themselves, so if you would prefer not to have your plants do this, just cut off the tall stalk after the flowers have bloomed, and before they set seed. I checked the list of Washington State Noxious Weeds, and did not find Verbascum there, though it can be invasive in other parts of the country (Hawaii, for example).

If you would like information about specific varieties of Verbascum, the Royal Horticultural Society A-Z Encyclopedia of Garden Plants has photographs and descriptions of many of them.

Date 2018-06-19
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Plant Answer Line Question

Keywords: Veronicastrum, Thalictrum, Actaea, Filipendula, Baptisia, Eupatorium, Berberis, Euonymus, Digitalis, Taxus baccata, Thuja, Verbascum, Helenium, Anemone, Ilex, Buxus

I am redoing the narrow planting areas (2-3' wide) on either side of our 20' long entry. Garages from next door townhouses butt up against the outer edge on each side, causing morning sun and afternoon shade on one side, and vice versa on the other side. I have picked out some euphorbias, heucheras, and carexes which should do well. I'm wondering if I should have some taller, more dramatic plants to offset these and if you have any suggestions of ones which might work. Also, any bulb ideas would be appreciated.


Have you considered putting up trellises on one or both sides? Then you could grow vines which require little width, but still have the advantage of height. You could also grow taller plants (maybe some grasses like Miscanthus or even a well-restricted--using root barrier--Bamboo) in containers, and keep them shaped to suit the narrow space. Some shrubs and trees are naturally narrow or fastigiate in growth habit.

Here is a list of narrow plants compiled by local garden designer Chris Pfeiffer,c2005. Some will be too wide for your planting area, but you might want to research those that fit the site.

American arborvitae 'Rheingold' (Thuja occidentalis 'Rheingold') 5'h x 3' w

Barberry 'Helmond Pillar' (Berberis thunbergii f. atropurpurea 'Helmond Pillar') 6'h x 2'w

Boxwood 'Graham Blandy' (Buxus sempervirens 'Graham Blandy') 8'h x 1-1/2'w

English yew 'Standishii' (Taxus baccata 'Standishii') 4'h x 1-1/2'w

Irish yew (Taxus baccata 'Fastigiata') 20'h x 4'w

Japanese holly Jersey pinnacle (Ilex crenata 'Jersey Pinnacle') 6'h x 4'w

Japanese holly Mariesii (Ilex crenata 'Mariesii) 3'h x 1-1/2'w

Dwarf yeddo rhaphiolepis (Rhaphiolepis umbellata 'Gulf Green') 3-4'h x 2'w

Heavenly bamboo 'Gulf Stream' (Nandina domestica 'Gulf Stream') 4'h x 2'w

Japanese euonymus 'Green Spire' (Euonymus japonicus 'Green Spire') 15'h x 6'w

There are also a good number of tall perennials you might try, such as (for your afternoon sunny side) Helenium, Verbascum, Baptisia, Eupatorium, and bulbous plants like Allium and Eremurus, and for your shadier morning sun side, Macleaya, Digitalis, Filipendula ulmaria, Anemone hybrida, Actaea (formerly called Cimicifuga), Lilium martagon, Thalictrum, and Veronicastrum.

There are many excellent gardening books you could consult for ideas. Since you have a small, narrow space, I highly recommend local garden writer Marty Wingate's book, Big Ideas for Northwest Small Gardens (Sasquatch Books, 2003). You are welcome to visit the Miller Library, where you can do further research and also borrow books.

Date 2018-03-01
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Garden Tip

Keywords: Vegetative propagation, Verbascum, Rudbeckia, Phlox, Papaver

Take root cuttings in autumn, once rain has arrived, to make new plants of many popular perennials like oriental poppies, verbascum, garden phlox and black-eyed susans. The September/October 2004 issue of Horticulture Magazine gives clear instruction on this easy propagation technique, and suggests many other suitable plants. In a nutshell:

  1. lift the plant to be propagated with a garden fork
  2. shake off soil to expose the roots
  3. cut out a few roots that are about the thickness of a pencil, noting the "top" of the root (closest to the plant)
  4. cut the root into 2 inch pieces
  5. insert the pieces into a small container of potting soil, with the top end just under the surface
  6. keep the container moist, not wet, and inside in bright light until new growth appears
  7. transplant into individual pots when growth is a couple of inches tall

Date: 2007-04-03
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May 31 2018 13:14:08