Do you remember when you first figured out that some plants look great for only part of the year before looking as though they had died, but then they popped back up the very next year looking like nothing unusual had happened?
When I see daffodils, which do exactly that magic act, I remember talking (maybe 15 years ago) with a young guy about his new home and its great yard. He was very concerned that he had already killed some of his beautiful flowers.
We eventually figured out that his flowers were daffodils. The guy just had not yet learned that some flowers (like daffodils) come up early, bloom for a couple of weeks, and then begin to die back for the year. At that time in the season, the yellowing, collapsed leaves were normal.
It was a moment of revelation! I do not remember the exact moment when I learned about the hibernation stage of bulbs and the plants known as “herbaceous perennials”, but I certainly remember when that guy learned. We talked some more about the strange ways of plants, and he was relieved to know that he had not killed his beautiful flowers.
Plenty of other flowers follow a similar life pattern. All of the spring bulbs (tulip, hyacinth, crocus, for example), Bee Balm, Anise Hyssop, Phlox, Bleeding Hearts, Trout Lily, Blood Root, and many more beautiful flowering plants do the same disappearing act for at least part of the year.
However, not many of our commonly grown food plants are herbaceous perennials, disappearing for awhile before returning. Asparagus is one. Horseradish is another.
Fennel does that same magic act, too. A few weeks ago, all you could see of my fennel plants was some bare, brown sticks poking out of the ground. Right now, in the garden, the fennel is starting to show some dense feathery growth around the base of those sticks. They are reborn! Magic.