Kniphofia are pretty tolerant of a wide range of soil conditions, so not sure you can make any hard and fast assumptions as to what your specific soil may be like just based on them. They DO need good drainage however, else liable to crown rot, so that may be one reasonable assumption. There are various home tests you can do to help understand your soils. 1) Testing for soil texture 2) Percolation/drainage test 3) pH test. This does require the purchase of a home pH test kit, available at most home improvement stores and garden centers. They are quite inexpensive - around $5 or so - and perhaps the most accurate of any of the home testing kits. But be sure to use distilled water as the testing liquid - regular tap water will skew results. And I'd encourage you to rethink your priorities with regards to the soil. The soil quality is the foundation for any successful garden and any time, effort or expense you devote to it is an important investment. It is far better to spend some bucks and some time in improving your soil before you plant than to waste money on unsuccessful plantings simply because your soil quality is not adequate. Many new gardeners make this rather unfortunate and hard to correct after-the-fact mistake. Also, because of your location in a pretty arid climate, I'd look into drought tolerant/xeric plants. Once established, these will need minimal attention in terms of watering and are often happy in lean or less than fertile soils. Many of those mentioned above would work provided your soil is suitable. High Country Gardens is an excellent resource for these types of plants. Here is a link that might be useful: High Country Gardens

Well, I don't know if I can tell you what Celine Forestier LIKES, but I can tell you her situation here. She is planted in a droughty, sheltered corner under the south side of a pepper tree, getting full sun for maybe 3 or 4 hours a day and filtered light the rest of the time. She was moved there, into the far reaches of the yard, because it did not look like she was even going to survive during those first several years (started from an own-root band), a very sickly-looking plant, but around year 4 or 5 finally took hold and has become a good but not overly-vigorous grower (she has MAC and an unknown climbing China on one side of her and Reve d'Or on the other -- there's no room to be overly vigorous!). The soil here is a reddish gravelly loam that shows an alkaline bloom in dry conditions. Mildew can be a problem here. She gets a touch of mildew in the early season, but I wouldn't consider her a mildew magnet. (I've tossed more than a few of those and Celine is still here.) She is a good rebloomer (2nd flush currently beginning after April's first flush, with regular cycles of bloom into the fall), but that also did not happen until she had been in the ground about 5 years. I imagine a grafted plant would develop faster. I do think her somewhat sheltered position here helps, too (the pepper tree provides a warmer microclimate in the winter and a cooler one in the summer -- Celine's exposed leaves will burn a bit during extreme heat, which we get a fair amount of in our summers). It is a delightful rose with unique flowers, in my opinion, but required patience in this case. When my daughter asked me which rose I wanted her to support with an annual donation in my honor at the San Jose Heritage Rose Garden, I chose Celine Forestier. This post was edited by catspa on Wed, Jun 4, 14 at 10:42

Well the diversity of answers on this question indicate that cultural conditions have everything to do with whether or not plants need support. Sure, some always do, some virtually never, but conditions of soil type, moisture, light, and wind exposure make a big difference. In my old garden, Jacob Cline was an upright plant which did not need any support (though I am not a staker/straightjacket gardener, and gentle leaning is perfectly OK with me). At the new place, with too much moisture and shade, it definitely flops. In dryish soil, Boltonia snowbank is pretty upright for me, but with irrigation tends to flop. There just is no substitute for your own garden and conditions. And one year may be different than the next..... I personally think there are better supports for Boltonia Snowbank than any Monarda. Choosing something that has the same season of interest might be nice if you are constructing a vignette for that season. I have a stand of Sedum 'Matrona' in front of one group of Boltonia, and they look great together. Any similar sedum would do the job, and the cultural conditions are similar. Grasses of almost any type are excellent supports for floppy neighbors. Pennisetums of any type are a good size for the taller asters. I love Boltonia 'Pink Beauty', but it is even much worse as a flopper than its white cousin. I have grown that wonderful floppy plant through Calamagrostis arundinacea brachytricha, and its shimmering lavendar blooms looked great with the mauvey inflorescences of the grass. Another great scaffold plant is Molinia 'Transparent' or 'Windspiel'. The pink boltonia flowers were displayed throughout the tall flowers of the Molinia, looking like a display of fireworks. Another great support for floppy Boltonias is one of the shorter shrubby asters. I really like Aster oblongifolius and its cultivars for this (October skies, Raydon's favorite). It is shrubby like a boxwood, and will provide contrasting color and similar season of bloom.

Yes on Malva reseeding. Not to the point where it is a pest though, because while I had seedlings to share for Spring 05, I had none this year. Boltonia gets big quickly - Mine got pretty close to mature height the first year. Each of the Boltonia plants are about 2' in diameter, in their 3rd year. My plants are in full blazing sun, at least 8 hours of it, and are fine. No supplemental watering either. Shrubby and not too tall is Caryopteris Worcester Gold, and the lighter foliage might be what you are looking for. I just picked up a Caryopteris Snow Fairy (variegated foliage, not too significant blue flowers), which would look smashing with Boltonia and all the other purples and blues you have. Which Salvia did you lose? I should have plenty of Uliginosa for fall and some Blue Cloud for Spring. Suja