Our groundwater is not only alkaline -- it is also rather saline, being ancient seabed.

I've found soil sulfur to be the most helpful thing here.

OTOH, I have come to the conclusion that avoiding roses with a lot of rugosa or a lot of multiflora genes serves me best, since I am not of a mood to pamper and plead with roses that are unsuited to my conditions.

Soil sulfur, acidic amendments like oak leaves & shredded pine bark.

Also, if you use chemical fertilizers, be cautious with using balanced fertilizers, as phosphorus tends to build up in alkaline soils & tie up other nutrients.

Don't know how applicable this is to your soil, but in our highly alkaline soil, the fertilizer of choice for fruit trees & berries is essentially pure nitrogen, in the form of ammonium sulfate. I'm cautiously using some on roses.

Gypsum (calcium sulfate) & sulfur are popular amendments, too. I'm new to the area, but I'm seeing some chlorotic roses now--plants grafted on I don't know what--multiflora?--which is supposed to loathe alkalinity. Haven't had severe chlorosis on any own roots.

I'm now putting most roses in a mix that includes at least 1/3 pine fines blended with a purchased truck load of native soil/compost mix.

Guess my bottom line recommendation would be to amend very conservatively with chemical fertilizers (salts) as you can kill a plant fast in hot weather with them. And long-term solution is to constantly add acidic organics like compost, oak leaves & pine bark.

A soil pH closer to 7 (neutral) than 8 shouldn't be a problem for most plants, including almost all roses.

Sulphur is the only real solution for long term improvement of soil pH, short of replacing half of one's soil with more acidic stuff. Even sulphur won't have much effect at tree root depths. Organic matter helps by acting as a buffer but will not easily improve a soil's pH by itself and any slight improvement will be short lived. A quick pH fix for chlorotic plants which also has some long term effect is digging holes to feeder roots level around a plant's drip zone, adding a mix of 50% sulphur and 50% iron sulfate and covering up. Rain or irrigation is required afterwards. This will work for most soils but the extremely calcareous ones.
Nik

You can order paper test strips with an appropriate pH range, or use the inexpensive Rapi-test meter as I do. Test kits are usually a waste of money,

Many roses are fine at 7.4, but others can have trouble getting enough iron even at 6.8. If you don't have symptoms of iron deficiency, don't worry about pH.

Our water usually tests between 6.4 and 6.5 . . .

Our surface soil is pH 6.5-7 which good for most plants except those ericacious plants that require very acidic soils like blueberries, rhododendrons, etc. The problem is our well water which is highly alkaline due to the dissolved limestone from percolating through the limestone bedrock. I also suspect that our subsoil may be more alkaline than the surface soil. Mulching every year with pine bark and fertilizing with alfalfa has acidified the soil and probably supplied low/missing micronutrients making the plants happier and eliminating any pale chartreuse and white leaves.

Cath

jerjen have you tested the electrical conductivity (EC) and sodium absorbtion ratio (SAR) of your water? pH is just one parameter which affects water suitability for irrigation. It is possible to have relatively low pH with high SAR and EC levels (e.g high EC not due to dissolved carbonates).
Having a lowish pH with relatively high SAR and EC might mean the water is reasonably suitable while a higher pH with the same levels of SAR and EC would make it unsuitable.
Nik

Nik -- Our entire area is ancient seabed. It's largely decomposed (or not) sandstone, with random inclusions of heavy clay. Because the aquifers flow through the old rock, the water is full of mineral salts of all kinds.

A representative of our Municipal Water District once asked me:
"You don't DRINK this water, do you lady?"

And, in fact, almost no one here DOES drink the water. We shower in it. We do laundry with it. We water plants with it. But water for drinking and cooking is always filtered.

So, I am unsurprised that the plants don't like the water. I don't, so I don't know why they would. In periods of drought (which we are in the 3rd. year of) various salts build up in the plants, and you can see them rather like a white lace border around older leaflets.

In most cases, water that is noticeably "hard" or noticeably salty/bitter will contribute significant alkalinity. The pH doesn't matter unless there are a lot of dissolved minerals. But don't use artificially softened water. Softening replaces largely harmless calcium with sodium, which is harmful to soil and plants.

Thanks for the knowledge all. I was just making sure there was nothing I should be doing knowing I had alkaline soil.

Thanks again

SCG

The recommended 'softening' method for irrigation water is reverse osmosis (i.e. desalination). Expensive both in one time and in running (electricity) costs, if one is to water more than a few pots and one has to find a way of responsibly dispensing the salty portion of the water produced.
Nik

SouthCountryGuy,

I'm in your position, added to which is slick, grey clay. You could make clay pots out of my soil, no lie.

I did all of the above suggestions, and still have isolated problems to which I throw sulphur and if really desperate (my grapes), Ironite. But it doesn't solve the problem completely.

When I plant more roses, I just rope my husband in for some serious digging. I try to dig up a LOT of soil around wherever I think the rose-roots could possibly grow in the future, and just amend, amend, amend. For beds, I just dig up whole swathes, and I make sure to amend many months before roses go in, to give the sulpher time to work in the soil. After planting, I amend some more. Sometimes it's all I do!

The good news is that I've read that clays contain more potential for health than acidy soils. I don't know if it's true (I've only been a rose nut for three years now), but I'm hoping it is, and so far so good!

NaCl here is still a problem in the groundwater and sometimes percolates out of the soil after a gully-washer. I don't know any other way of dealing with it but amend, amend, amend. But out of about 2 dozen antique roses I have so far, only one is looking sad (winter damage, but recovering), so, for the time being, Randy and I must be doing something right.

The only ammendment I know that works in sodic soils (too many Na cations) is agricultural gypsum.
Nik

Thanks blushing. I did do an amendment of the total bed, well partially as my sandy loam grows pretty much anything, just ask the weeds :).

As per nikthegreek suggestion I am going to add some gypsum around my roses. I, like jerijen, am not into pampering but with only 40 roses I can afford a bit of time.

I, again, appreciate all the expert advice.

SCG