I planted a hillside xeriscape garden, last fall, and those little 4" (pots) plants are taking off, now that the weather is warmer. I've been looking searching for guidelines for feeding the plants & mostly see references to fertilizing in the fall. I'd appreciate input about feeding my plants and/or composting around them. Will compost be too nutrient rich for these plants? Is spring fertilizer appropriate for these babies. It looks like the penstemon & agastache don't like much food or water, but I'm not sure about the rest. I'm used to amending amending amending, but need to educate myself.
I'd also like suggestions for watering on a hillside - how do I deep water, when the water tends to drain down? I've read that drip irrigation may not be the way to go & I live in a temperate area, so I don't think these plants will need much irrigration, once they're established, so I don't want to install irrigation, if the labor won't pay off, down the road. At the moment I'm hand watering, but that's taking forever!
These are some of the plants I have:
mexican feather grass
I'm working through this same thing. Its not always a simple question because the information isn't always there. A number of those don't like real rich soil. Can't say for all. Also, breaking Genus down like Salvias or Agastaches yields a fair range in tastes. Where I'm at on this is:
1) All plants need a basic set of minerals. Outside of Carbon (and Oxygen), these are obtained from the soil and microbes in the soil. Get a soil test and find out what your soil is low in. Add mineral fertilizers to supplement. Examples include greensand, which is an Iron-Potassium-Silicate that in addition to the iron and potassium has a number of trace elements; Planters II, which is a trace element fertilizer; Cal-Phos, which is a soft rock calcium phosphate. There are others. This gets you a baseline so you don't have deficiencies. It doesn't add organic matter.
2) Drainage is critical for many xeric plants. What you do depends on your existing soil and what you plant.
3) Some xeric plants like ammended soil. Others do not. Many years ago I planted a number of "xeric" plants I got from the nursery. Many of them were languishing so a worked some compost into the top of the soil. Most of them did better. One that had been doing well promptly died. A reason I've readd is that ammendments and consistent moisture allow pathogens to grow that the plants don't have defenses for because they haven't seen them in generations. This is coupled with symbiotic relationships with mycorrhizal micro-organisms that form in dry soils but not in wet, rich soils. The beneficial microbes help fend off the pathogens. If the relationship isn't there the defense isn't either. I've come across accounts of plants commonly living less than 5 years in ammended soils but greater than 20 years in non-ammended. I consider myself to be investigating this and not an expert, so just take it as that.
4) Plants need organic matter and Nitrogen. Best info I have is to use organic mulches at the soil surface.
5) It is easier to add more to the soil than it is to add less. Much easier. Fertilizers or composts can be added when the need is observed. They can't be taken away.
I know that yarrows hate any kind of amendments or mulch. They like 'plain old dirt', I gues you'd say. Agastaches need excellent drainage and do well if you place them slightly above ground level with some rocks to assist in drainage. As for the rest of the plants, I'm not sure, but I'm sure about the two I mentioned. Good luck!
I will take the less is more approach for amendments. I will heed your advice to test my soil, so I'm adding the appropriate "stuff". I'm also participating in the "myco" coop & have high hopes that this product will help.
Crazymary, I'm not sure if this one is a native... I'll check the tag this weekend, if it hasn't disappeared during the winter. I'm just assuming it will work in my garden, although I do have a couple of penstemons in the front yard that are thriving in an ornamental bed that gets quite a bit of water. Guess I'll play it by ear...
More than likely the myco is already in your soil, crazymary. Adding some shouldn't hurt though. A study on Ceanothus I read found that the myco relationship was established in poor soils, but not in rich soils.