Certified GKH Gardening Expert
My research says artichokes in cold climates are often treated as annuals - meaning, they are replaced each year. However, Cornell University in NY offered this info:
Shorter season varieties that are more likely to flower and winter over in New York include:
Imperial Star - grows just 3 feet tall
Violetto - purplish buds
Grande Buerre - spineless heads, grows up to 9 feet tall
If you want to try overwintering artichokes, dig up the root crown and put it in a plastic bucket with some kind of insulating material, like leaves, newspaper or other mulching material. Thenn wrap the container in burlap or a frost blanket and try to keep it from freezing. They should withstand a light freeze.
You should be able to get them through the winter if they don't freeze too hard. They can withstand cold temps, but not for long and not too cold.
For your hibiscus, this could be a few different deficiencies, but most usually nitrogen. These plants are very hungry and need feeding every few weeks for the best results. This is especially true for container plants.
This article will help you to understand some of the most common reasons for yellowing leaves: