I had many kinds of citrus planted in my yard in San Diego and the blood orange grew the biggest, up to the top of the roof, and yielded great. It was planted by the house foundation where it could run its roots under the concrete. Perhaps some concrete paving stones around the plant could accomplish a similar environment. I have a caution about redwood compost. Back then I used redwood compost in some planting holes. Some fruit trees seemed unaffected but I planted a persimmon and it declined over 3 years and died. I heard about possible allelopathy in redwood (compounds that hurt or kill other plants), so I removed all the dirt from that planting hole and replaced it with fresh soil. I planted an apple there and it did great. I was just looking on the internet about that topic and some studies seemed to indicate treating the soil with activated carbon could help cancel the allelopathy. Whether the redwood is affecting your plants or not I don't really know. Just a thought.

pruning is not necessary. spireas are pretty tough plants. Something major must be going on to distress them. how were they planted? where were they planted? are other plants nearby doing okay?

Currants can be grown in the shade in our area but expect little production out of them. all the whites have failed at my house, although they are the most unique currants they fail in the carolinas. When retailers say to zone 8 they are talking about the pacific Northwest and they can grow in full sun there up to a solid zone 8 there. The blacks have produced in full sun in my yard but like the shade more the reds have never produced but are alive. The whites have all crooked, I've tried about 30 different varieties over the past 3 years and only about 8 varieties are left. I've found morning sun is key with protection from the sun during the hottest part of the day. They make great understory plants but benefit from a raised bed with a cardboard layer at the bottom to give the currants a chance to establish before feeder roots from the canopy tree invade the soil space. This also stops suckers from popping up beside your currants because you won't damage the canopy trees roots from digging in the soil. Many trees including pears, nut's, persimmons, etc will send up suckers anywhere the roots have been disturbed or exposed. Currants are also far from drought tolerant so be sure to water when the soil gets dry but avoid wetting the leaves when you do water. Ahhh the things we do to grow things out of the norm..... Good luck

Down here in South Texas, where we have very high temperatures and humidity in the summer, nasturtiums will not survive. The just wilt away, but they will come back in the fall. We refer to them as a cool weather herb, and plant them for the winter months since we seldom get a freeze. Is it possible that you have had a extremely hot summer? And yes, they are very wonderful in salads and even on cold meat sandwiches. And try them as a garnish on a salad plate for dinner party and hear all the comments.