Hello there! I recently added on to my garden and am looking to move 4 perennials. One is a yellow yarrow that was planted last year, a salvia rose marvel that was planted last year, a purple coneflower planted last year, and a coreopsis that was planted this year. All 4 plants are in bloom and currently flowering. Is it safe to move around the plants now or would it be better to wait for fall or spring? I am in zone 4 in Minnesota.
Summer is the worst time to move plants. Your best bet is to wait till fall. You need to do it at least six weeks before the advent of cold weather so the plants have time to become established. Here is more:
https://www.gardeningknowhow.com/ornamental/shrubs/shgen/best-times-for-transplanting.htm
Hot lips flowered last year, but not this year, also some penstemons. I would also like to plant a hibiscus, but wonder what would be necessary
The top reason plants do not flower is lack of sunlight. Are these planted in full sun - six to eight hours of sun a day? A perennial hibiscus needs full sun to bloom well. Hot lips salvia will lose the red when it gets hot but return as the weather cools. Peonies are spring bloomers. If they have been moved, they may not flower for a year or two. Penstemons are typically spring bloomers. Be sure to mulch and water all your perennials. Check your growing conditions against these tips:
https://www.gardeningknowhow.com/ornamental/flowers/asters/aster-plants-dont-bloom.htm
https://www.gardeningknowhow.com/ornamental/bulbs/red-hot-poker/growing-red-hot-torch-lilies.htm
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/outdoor-hibiscus-care.htm
https://www.gardeningknowhow.com/ornamental/flowers/penstemon/penstemon-beard-tongue.htm
https://www.gardeningknowhow.com/ornamental/flowers/peony/peony-bud-blast.htm
I didn't get a chance to put my perennials in the ground before the ground froze, where should I store them? Outside, in the garage or basement?
Unfortunately, this depends on the type of plants in question. You will want to treat them as they would in their native environment. Tropicals will need to be grown indoors, and anything that would naturally go through a dormancy will need to be put to sleep. This article will get you started with storing bulbs that go through dormancy: