The 3rd strawberry plant is still producing strawberries but not sending any runners out.

Also, when winter hits, or before it hits. Should I just bury them under more mulch to protect the roots?

I have the Tri-Star strawberries. In regards to production, it all depends on the type of strawberry plant that you have. Some create strawberries just once in the season, others twice, and some will produce all season long.

Runners do take energy away from the plant and from producing strawberries. But it is also important that you have these runners - because you need to change out your strawberry plants about every two years. So if you planted the mother plant this year, you can then replace the mother plant with those strawberries two years from now. If they are left for over two years, the strawberry production typically drops off.

In regards to overwintering - I didn't do anything for the strawberries last winter and they all came up very well this year. A few died out of the 50 we have planted, but I had some runners that I planted in another spot over the winter to use as replacements just for this instance.

There are three main types of strawberry plants: June-bearing, everbearing, and day-neutral. The June-bearers produce one harvest of usually-large strawberries in the spring or early summer, depending on climate. The everbearing strawberry types will usually produce an early harvest, late harvest, and an occasional 3rd harvest. The day-neutral varieties produce continually. The plants you purchased from Lowes were probably either everbearing or day-neutral.

Day-neutral plants generally produce the fewest runners while June-bearing ones produce the most. Any strawberry plant that produces runners prior to setting its last strawberry will divert productive energy away from the berries and to the runners. But, allowing the runners to root and establish themselves prior to the next growing season will give you more strawberry plants and, consequently, more strawberries for year two.

As for over-wintering, your climate will probably dictate, but strawberry plants can be tremendously hardy. Many varieties will survive an ice storm and 6 inches of snow with no apparent harm the following spring (this was my situation in Kentucky two years ago with a June-bearing variety).

The experts, however, recommend taking better care of your plants. Strawberry Plants.org is a great free resource for just about everything related to strawberry plants. In their Growing Strawberries and Strawberry Plant categories, they talk about overwintering, transplanting, runners, propagation, and a host of other things.

Also, they have a database of strawberry varieties and a ripening chart for the June-bearing types on the Strawberry Varieties reference page. I hope that helps!