Is it just the colour of the leaf or are there changes to the texture - crispy or wilted or anything like that?

Could be pythium, or root rot. If it is, treat your water with 500 ppm hydrogen peroxide to control it. You don't say what nutrient concentration is, so determining if you are overfeeding is difficult.

There's definitely a water-transport issue going on here. Is the soil moist in both the containers and the ground? Yes Grab one of the poorest ones and pull it, then have a look at the roots and lower stem. Look for nubbles along the roots or cankers on the stem. no nubbles or cankers Then take a sharp knife and slice the stem down to the pith right at the soil line. You're looking for brown or black coloration either in the wood or in the pith, hollow stems, or anything else that doesn't look like fresh green healthy plant. all looks green from the inside. The problems appear to go from the outside in. Also check the brown tops. Is it kind of a purplish-brown, or black, or real dirt-brown? Are the new leaves distorted at all? New leaves look absolutely healthy. When I put on my strongest glasses (I have several different pairs from different eye exams over the years) I saw that there appeared to be very tiny holes being made in the leaves that were browning, but not yet crispy. Then I saw tiny, tiny green insects. So would they be the culprets or are they just taking advantage of a sick plant? I feel lousy about this. I usually stand guard over my plants and check them several times every day. But we've had to be out of town a lot these past few months. Thank you for your help.

Hi Prairie_north: I check on Pro-Mix HP (65 to 75% peat moss, perlite, lime, wetting agent) http://www.pthorticulture.com/en/products/pro-mix-hp-mycorrhizae/ "PRO-MIX® HP MYCORRHIZAE™ HP - high porosity PRO-MIX® HP, with its high perlite content, provides a growing environment which benefits growers looking for significant drainage capacity, increased air porosity and lower water retention. The added benefit of a fibrous peat moss and coarse perlite ..." I notice on the last picture, the pot is sitting against a black saucer, which means water won't drain fast enough. Rugosa HATES WET FEET. Rugosa is known as "beach rose" since it thrives on DRY & SANDY SOIL. The Pro-Mix-HP has fibrous peat moss, which doesn't drain well like sand, plus peat moss when gets too wet, become acidic. Tip-wilting is indicative of acid-burns ... years ago I had the same problem with one of my band in an acidic too wet potting soil. How to fix that? Take the saucer at the bottom out, and use 2 wooden planks to elevate the pot, to air out the bottom. If possible, drill extra holes at the sides around the bottom, to drain off excess water. pH-test the soil with red-cabbage juice. The best potting soils I used become "clear" in red cabbage juice, which means it's a good buffer & neutral pH. The exception is MG-regular-potting soil (green bag for indoor plants) with a higher % of peatmoss, means more water-retention capacity, that became light pink in red-cabbage juice I still have problems with the over 65% to 75% peat moss content. I would add more perlite. When I root roses, I use 1/2 perlite to 1/2 potting soil (already has perlite), yet that doesn't drain fast enough, I have drill extra holes at the bottom of the pot. Rugosa doesn't like fertilizer, so aim for fast-draining, that way you won't get minerals-accumulation either from your tap, or excess fertilizer. I really think the saucer at the bottom is the culprit. That's why stores put their rose-pots on wooden-planks, for best drainage and airflow to the bottom.