I'm at 500 ft Portland and my arctostaphylos that is supposedly hardy turned black all over. I think the largest branch is stil alive, however, as it has a few small leaf buds. We are also replacing Hebes with other plants.

Forgot to add, all roses are doing well, including those in large pots.

If a plant does not do well in the zone you llive in they tend to die off in extreame weather. like extreame cold or excessive heat. check out your zone then check out the zone recomendations for your plants. Then check out things like what diseaeses the plants are prone to and see if you can identify any diseases. Then check for pests. Then check around for herbicide or pesticides. And always check the way you are caring for your plants with what care the plants require. it helos to look into these things so you can narrow down what is going on with a plant.

I'm at 250 feet in Portland, and all roses in pots lived (even the small pots) when it got to 14 degrees for several days. But we did lose Yuletide camellias, tetrapanax, and even some windmill palms (trachycarpus).

Some plants other than roses do not like weather extremes and sometimes they too can be prone to diseases. the they might also have gotten stressed out due to weather extremes. This added stresss could have easily lowered their ability to fight off diseases. This lower disease resistance might have also led to premature death from disease or rot. if it was raining a lot, f for example, the they might have gotten rot and died from this. or they easily could have gotten a disease due to stress from cold wet conditions. black spot is particularlly fond of cold and damp conditions. if the black stuff comes in spots it is likely black spot. in this instance i would not plant any new roses where plants have died. try something eles first like daisies. or maybe sunflowers. something easy to grow but hard to kill that favors your zone and weather conditions would work out really well. Daisies tend to be annual flowers. but they are very difficult to kill. Flake Daisies (also called African Dasies by my familly) are very hardy. plant them in october and the will bloom and grow from march until the end of august or September.

That is some of them that bloomed in our backyard just this March. Can be invasive though. so try to keep them confined to the area you plant them in. all the ones that bloom in our backyard are volunteer plants from the original seed package. The birds like goldfinches and our Montezuma quail seen to like to eat the seeds sometimes. They will also produce many seeds. you can harvest the seeds if you want to.

It was the worst winter for broad leaved evergreens since 1996, according to experts that have been pushing horticultural limits in Portland for a very long time. I'm in Dallas, OR (400ft). My Sarcococca are a mess. The one by my patio looked so bad I just moved it to another spot where I don't have to look at it! Euonymus japonicus Green Spire has all dead tips. Many other of my BLEs have major damage, Pittosporums probably hit the worst. A lot of evergreen azaleas in my neighborhood look half dead (but will probably be fine, if watered this summer). My figs have 1-2" dead tips but this seems to happen most years, even up in Seattle, never really affects fruiting.

Your roses, however, that's surprising, Portland being the rose city and all. Might be a combination of soil being too wet (which makes all plants more susceptible to harsh winters) and the January Arctic Blast.

1,600 feet, that's pretty high. If you had a thermometer that records lows I bet you would be shocked by how cold it got, and for how long, during the Arctic Blast in January.