I am looking for a tall perennial that would work well with Pacific Coast Iris (PCI). I am in zone 8, and the spot I am looking for is in the northeast corner of two fences. There is a small Kousa dogwood (planted last year, only about 6 feet tall) 5 feet to the left of the corner. The area gets a lot of morning and early afternoon sun, but is shaded from hot afternoon sun by the fence. As the dogwood grows, it will also provide filtered shade. What I want is something long-lived, that I don't need to stake or divide every single year, and will thrive in the same conditions as PCI (doesn't like regular water during summer, sun to partial shade). I want it to be at least 3 feet tall (so it will be taller than the irises), with flowers at a different time than the PCI, preferably midsummer. I would like flower color anything but hot/dark red or orange. I like peaches, yellows, white, pinks (soft or hot), purples, blues, etc. I know this is a lot to ask for, but I am looking for a very specific plant for this corner, and don't want to settle on something that isn't right. Any ideas?
One thing that comes to mind is that you will probably now have to water this spot for it to please the dogwood, an east Asian species adapted to summer monsoons. People are planting them everywhere up here now, where a great many of them fade and droop/roll up during late summer. Portland is hotter in summer than Seattle. So, the new perennial may not have to be drought-adapted. For good flowering you don't want the irises to become overtopped and shaded either, these are strictly open-site flowers that while persisting for long periods under forest conditions do not flower there. Consider western bleeding heart (Dicentra formosa), not taller but otherwise could be quite suitable. If there is any size to this area perhaps several additional kinds of flowers could be added, rather than trying to come up with a single variety that does everything you want.
I know that my dogwood needs water, but I thought that the corner was far enough away from it that I could plant something slightly different. I guess I am wrong here? Should I think about putting the irises somewhere else if they don't get along with the dogwood's watering needs? Portland does have hot days in summer, but it also rains in summer. Last summer was incredibly mild, with a lot of rain in August, and a good portion of the summer overcast and in the high 70's to mid 80's. I planted the Kousa because of its anthracnose resistance. I probably should consider more than one flower for the corner. It's about 5 feet from the point of the corner to the round edge of the bed. I wanted a little carpet of PCI in that corner, with something taller right back in the point of the triangle... It really is a very sunny corner, right up against the southern side of my north fence. Would bleeding heart do okay in that much sun? I had read in Sunset Western Garden book it prefers mostly shade. I have already looked at hollyhock, delphinium, digitalis, penstemon, campanula... they each have some of the features I am looking for, but for some reason don't seem to fit exactly. Maybe the plant I want doesn't exist!
Portland has a modified Mediterranean climate, same as here. Precipitation is concentrated in winter and falls off markedly in summer, making summer irrigation necessary for best results with most plants not specifically drought-adapted. "Cornus Kousa ---Kousa Dogwood ****Too thirsty. It loathes our dry summers and is horribly stunted. In this regard it is just like the Katsura. Happily, Kousa Dogwood will not grow too large for small gardens. I love the tree's appearance, health, and its colorful seasonal displays. But because of its virtues, and despite its thirst, it is being overplanted. It blooms in June, and Seattle would benefit by more trees that bloom later in summer" http://www.arthurleej.com/a-overplanted.html Of those you listed penstemons have a long season and some hybrids have a pretty bushy habit. 'Andenken an Friedrich Hahn' (syn. 'Garnet') is an example of an excellent sub-shrubby hybrid penstemon.
Darn it, I wish I had read that before I planted the Kousa. I also have a small japanese maple in my yard - that I didn't plant, but I have two of the worst offenders in my yard! The dogwood was only planted last June, and seems to be doing wonderfully - it is in area in my (very small) garden where it gets water because it is right next to everything else that needs it. Plus, I knew I would have to water it for several years at least, it being newly planted. I had never read anything about it being so thirsty though, thank you for the heads up. Now I know how to care for it in the years to come. The penstemon looks lovely. What a beautiful flower color, and I love that it has evergreen foliage.
For the yellow, coreopsis grandiflora (tickseed) might just fit your location. There is a corridor of sorts (temperature range) that runs fairly close to your location that might just allow the tickseed to work. Further, it has an extended blooming season. Self seeding, unwanted spring seedlings can just be raked away, or, transplanted. It is recommended that the clumps be thinned every third year or so. Good luck.
Why not go simple with Bleeding Heart? Doubt it would matter much where that corner was if it's under a dogwood. You could probably gain 28" out of Bleeding Heart in time.
I was thinking about the bleeding heart, which is lovely, but as I watched the sun move across the garden yesterday, I realized that spot gets a full 4 hours of sun in the morning. Would bleeding heart work with that much sun? I probably didn't make myself very clear, the corner is not actually under the dogwood. The tree is very young, just planted last summer, and still rather small. No branches actually hang over this area. It is planted to the south of it, however, so as the sun moves into the afternoon, the tree provides a little bit of filtered shade. As the sun continues to move, the east fence throws a shadow on the area, shading it from the hot afternoon sun. I am sure in several years the dogwood will be big enough to shade the area more in the early afternoon, but I think it will still get the morning sunlight for quite some time. Thank you for the coreopsis suggestion! Sometimes the problem with gardening and designing is that there are too many options. I am now considering a shrub too for this corner, since there is room for it... I have too many possibilities. :)
Yes: Where you have a deciduous tree it makes an accent point in the garden and should be faced down with low evergreen shrubs. Photinia davidiana undulata looks good with Cornus kousa. The best appearance is produced when the border is fleshed out and enframed with evergreen shrubs (mostly broad-leaved here in coastal NW, as we have a mild climate and do not have to rely almost exclusively on comparatively somber coniferous shrubs as they must do in frigid winter climates). Deciduous shrubs can be used to make a transition between these and the herbaceous plants such as perennials, annuals and bulbs which should make up the major portion of the planting except where the funds, time and interest are not present for planning and keeping up these kinds of plants. A good balance is a few trees, some shrubs and many herbaceous plants. Where a fence is being used as a backdrop climbing plants can be used on the parts behind the herbaceuous plants.
A 28 inch bleeding heart would be Dicentra spectabilis. The local native one that has compatible naturalistic character with Californicae iris is D. formosa.
Often if you're looking for a flower or flower colour you've missed the first step, which is to determine what plant shape you're after. Flowers make only a brief impact in the course of the year; the foliage is the dominant characteristic of the plant. And consider other characteristics, such as dormancy - some Dicentras are dormant by late summer, and darned ugly just prior to that. For my taste, a plant with big wide leaves would go with the upright foliage of the iris; Acanthus mollis for example. It is pretty much evergreen here. Hostas might also work - conditions sound fine as they are adaptable plants. Lobelia also comes to mind - basal rosette yields tall flower spikes of strong colour. Cimicifuga might also work, though you won't get much purple out of the purple leaved ones in shade. I'd also consider Hellebores or Bergenia. None might be just the PERFECT plant, but I think you could make a lot of those work. Anemone hybrids... honestly, there is a plethora of options, and I know I'd have trouble choosing just one. Be aware that Anemone and Acanthus will be hard to remove if you plant them and then change your mind, though. But I would tend to spin ideas involving an evergreen shrub, broadleaf or needled such as a dwarf hemlock or yew, as well as THE perennial you're after. You might also not get it right first time. That's half the fun of gardening - it always offers an excuse to go shopping!
Thank you for the feedback RonB. Very useful stuff here. KarinL, I like your suggestions as well. You are right, I was thinking of space (something taller in the background) and color, but not plant/leaf shape. I have been looking at evergreen shrubs in my Sunset Western Garden book, does anyone have experience with Abelia? It seems to match some conditions, and the pictures online are lovely. Or Cryptomeria Japonica? I have seen some dwarf versions, only in pictures, so I am not too sure of the size/scale of this plant. I do have a lot of other japanese plants in my garden though - acer palmatum "red dragon", the cornus kousa "satomi", hakonechloa, nandina domestica, and pieris japonica, so maybe that would fit the look.
Later the dogwood will have winter bark interest that could be related to with texture and coloring of some of the dwarf cryptomerias. Both Japanese cedars and abelias are popular and frequently offered here, there are new selections of the latter continuing to come out. Emphasis seems to be on low growth and variegated foliage. Winter foliage coloring of abelias might also go well with dogwood bark. Best leaf retention may be found on A. x grandiflora, even that not fully committed to retaining much coverage through spells of sharp cold. Rest of the time same bronze-green foliage color group as the Photinia. (For more on naturalistic character, foliage color groups and combining plants of different types in mixed planting see the excellent Grant/Grant, GARDEN DESIGN ILLUSTRATED - not currently I believe in print but reprinted many times over prior years and fairly frequently seen at Half Price Books outlets (for about 5 bucks or so) and on the shelves of public libraries).
