Heat tolerant plants - beginner needs advice

My husband and I live in Washington State, but those familiar with Washington know that the southeast portion (our location is zone 7b, I think) is very different in climate from the west coast. We are currently relandscaping our huge yard, using some ideas from our former home in the same area several years ago (landscaping was done by a local professional). The problem is that our yard is 4-5 times larger, so we want to add some different plants, as well.

We are not really gardeners, we are engineers. However, from previous experience we know that a well planned landscape can dramatically reduce the maintenance that is required to keep things looking nice and colorful throughout the growing season. The flowering plants that were successful for us before were: coneflower, yarrow, rudbeckia, roses, rhodies (in the shade!), azalias (in the shade!), and potentilla. We tried scabiosa, and they did not do well for some reason.

My biggest question is this: The zone designations seem to describe hardiness with regard to winter conditions - what about 100+ degrees in the summer? Our area has a very hot summer during July and August. Is there a way to gauge a plant's tolerance to heat by the descriptions that are found (for instance) on Dave's Garden? My concern is that when I go looking for plants based on my zone, degree of shade, and pH of soil, I will come up with plants that may be incompatible with the heat in this area. For instance, we are planting pine trees to shade the house, and we plan on trimming them about 4-5 feet high underneath so we can plant flowers underneath. Recently, I serached for light shady plants, slightly acidic soil (from the pine needles), my zone, and came up with Jack in the Pulpit - which is a forest plant and I am pretty sure would not survive!

Other than hanging out at local nurseries (which is pretty hard for us because of work), is there another way to tell what plants are heat tolerant? Thanks for your help!

I totally understand your dilemma. I've got a couple of suggestions. 1. Look at the yards around you and on your way to work. What are your neighbors planting that seem to thrive?
2. Contact your local county extension agent. You might also look on-line. Sometimes they will have suggestions for your area on-line.
3. Going to the nursery does take time, but if you can make it early in the day (before it gets busy)---if they have a master gardener (or some other licensed gardener) on staff, they really can be very helpful. You can also take a sketch of your yard and they could help you with what might look good.

Hope this helps.
Annie

I would highly recommend picking up a copy of the Sunset Western Garden book. They have come up with their own set of climate zones which factor in winter temps, summer temps, rainfall, and other things so that if they say a plant grows in your Sunset zone, you can be pretty sure it'll do well for you since they've taken all the important variables into account that the USDA system leaves out.

iris, asters, daylilies,artemisia,lamb's ears, trumpet vine, butterfly weed,nepita,russian sage, hawthorn trees, ginko trees.
you might have trouble with plants under pine trees as they suck up all the water.
hawthorn's are in the rose-apple family. they will tolerate heat are smallish and provide wildlife interest plus spring flowers and berries.
i have the same trouble as i am in the prairie, where i need plants that are able to stand the transition from winter to spring and the hot dry summers.
you might also try bur and chinkapin or shumard oaks. amur maple. spruces might work better than pines, at least here. i love the hoopsi spruce. they are an ice-blue color and seem to cast off the heat. overall it sounds that prairie flowers and grasses would do well in your area. peonies.

oh and bulbs, tulips (darwin,species, greigii,triumph), lilies etc. most bulbs like to bake over the summer after they flower.

Wow - THANKS!! I really appreciate all the input - especially the reference to the Sunset Garden Book! I just looked it up on Amazon, and I can get it very reasonably. Looks like I have a purchase to make!

We do have a bulb bed planned - so we got that far, at least. Tulips, lilies, daffodils, hyacinths, mucsari, and re-blooming iris (my attempt at stringing color along as long as possible). I noticed that Len123 mentioned a particular kind of tulip - do they vary quite a lot with respect to heat tolerance? Usually it doesn't get hot here until late June or July, so I would not expect the plants themselves to get baked (except the lilies and iris) - but I didn't think about the bulbs underground. I haven't bought anything yet - fortunately still in the planning stages.

I will definitely check out some of the other plant names mentioned - some of them are familiar, but some are new to me - which was the purpose of this whole posting, so thanks again!!

I'll undoubtedly have more questions, so thanks and stay tuned! :)

the tulips i listed are more inclined to last more than one season.

I guess I have a lot to learn - I thought all bulbs came up repeatedly! Thanks for saying something about it!

Daylilies are great! We have really hot summers also, and they can take it.

They are so beautiful, that you can get addicted. They are no longer the old yellow trumpet shaped flower people remember. You can check them out at daylily.com which is an auction, or from Flynn Daylily Gardens, or Ridaught Daylily Farm. There are several good growers of daylilies.

Check out High Country Gardens. They carry only plants that survive in the hot regions of the west. But it gets real hot down here in Mississippi too and I've ordered some things from them. They ship their plants carefully packed and all of mine have gotten to me in perfect and healthy shape. They have an online catalog.

Hi, bjhickman:

I second all the comments above (esp. picking up some texts) and would suggest getting some reading that has to do with your state/region specifically. Sunset covers the west coast well, and a book about Washington state, especially your more arid region, would be worth it's weight in Au (your comment about being engineers rings a bell -- former metallurgist here).

I've only been in Washington once, but understand that conditions vary widely from west to east across the state. Being hot in summers is only part of your story; isn't it rather dry for a good part of the year too? Your soils will have a role to play as well, supporting some species but others -- not so much. This is where knowledge of your local flora will help a lot, so that you can use these species as well as introduced types of sympathetic qualities. If your proximity to the Columbia River means you have all the irrigation you want, then water management isn't as important as for other xeric climate gardeners.

It gets really hot here in KY in the summer -- but it is humid. For you, factoring in not only high and low temps, but average rainfall and soil texture/structure while sorting through the incredibly diverse choices of plants that you might grow (remembering some of the complex calculus equations and multiple variables about now) is important.

Many of the bulbs mentioned above will probably do perfectly fine for you, since they "do their thing" from late winter to early summer, when they go dormant. There's the "mimic" that works for your climate. Finding the rest of your designed landscape that fits isn't as easy, but still fun. Don't count out all the forest/woodland understory species like Jack-in-the-pulpit; many of them also are spring ephemerals which take advantage of the light/moisture/cooler temps of the spring, and fade into dormancy by the time the really hot and dry conditions roll in.

Finally, source other DGers from your neck of the future woods. There is a fine gentle soul, rutholive, who has gardened for a bit of time in eastern Washington. She could offer some sage advice (or Salvia).

the problem for me finding books for my area, is that the authors want to sell more books so they take too large an area into consideration. I don't know how many "great plains books and gardening in midwest or Missouri. but even missouri has so many areas and climates, i'm in the tall grass prairie but north of the river is the glacial till region, the ozarks, se mo is more southern climate, cotton etc. they have numerous plants that don't work here. not to mention the micro-climates.
city folks with a 1/4 acre yard are more likely to water, amend, fertilize etc. than country folk with a 2 acre front yard.
i've discovered that it's not so much the winter hardiness but rather the transition from winter to spring, the soil and heat and drought tolerance. my wild weedy mexican fire plant and florist anemones don't know that they're not suppose to overwinter here!

Thanks, NatureLover for the additional reference for purchases - I will definitely check them out. It looks like many of the plants that are hardy for this area are also available from Sooner Farms, and I see that Daves Garden has a fairly good review on them (located in OK in zone 7, but I'm sure a lot more humid than here). It will be good to have several sources from which to shop!

Yes, ViburnumValley, it is a tad dry here - 6" of rain a year! Looks a lot like the Mojave desert with hills (just substitute sage brush for the Joshua trees!), but as you pointed out, water is no issue because of the Columbia River. I don't know that much about the chemistry of the soil, but I do know that drainage is not usually a problem. It is a tremendous agricultural region, with lots of fruit and vegetables, vineyards, etc. so the soil must be pretty good as long as you keep it watered. I suspect that it might be very slightly on the alkaline side because we used to have roses next to our house and we were advised to keep the Miracid on them very regularly to combat the concrete leaching into the soil and causing it to be too alkaline. Also, Rhodies and Azalias have to really be babied along to do well here - maybe a combination of the soil and/or the heat.

Len123, I know just what you mean about books for your area! I suspect it would be the same with Washington State.

I guess I need to take a list of candidate plants down to one of the nurseries and talk to them about whether they are viable options or not. I know that many are, but I really want to try and have semi-continuous color from early spring through fall, and that is getting me into some names with which I am not familiar.

Thanks - good advice is worth all the Au and Ag in the world (for you, Viburnum Valley)!!

What about gallardia daisy?
They bloom for a long time especially if you deadhead them.

The AHS has a heat zone map; it may help you pick out plants that can survive through your summers.

http://www.ahs.org/publications/heat_zone_map.htm