Still time to cover plants if needed.

Who needs to get covered in the winter and why do we do it? If you started with plants that are for zone 4 or colder regions like zone 3, and planted them timely....they should not need to be covered. A zone 4 plant should be able to withstand our winter climate as it is. Trouble is....the same plant can be found in multiple sources that will all have a different zone listed. Zone 5 is south of us, starting mid Iowa. Zone 3 is north, starting by the metro area. If I find conflicting zones listed, I check about 3-5 sources on line, looking for an information site, not a sales site. In theory.....zone 3 plants here should never need mulching and zone 5 will always - and still they may not make it-wrong plant for our climate. There is our course always exceptions. Case in point; my Pink Delight Buddleias rated as zone 6 (think southern Missouri), that not only they survived 2 winters here, but survived in 2 gallon pots! Amazing.
There are different reasons to 'winter mulch' plants.
Plants that were installed late in the season: 6" of mulching these will help to insulate the surrounding soil, keeping it warmer longer, to allow a little more time for root growth. This will be especially helpful to plants that you perhaps moved or divided too late or too small in the season.
Plants with shallow root systems like strawberry & mums: mulching helps these types when spring rolls around. The freezing & thawing that we have in the spring, warm days & freezing nights, pushes the plants out of the ground - a process called 'heaving.' The mulch material helps to keep the temperature directly near the plant more even until spring is really here.
Plants the can be semi-evergreen like some types of daylilies, ground covers, geranium etc: winter mulch helps to keep these types from drying winter winds if no snow cover is present.
Another good reason to cut back in fall - no foliage to dry out.
Mulch does not keep plants from freezing, most years the ground freezes several feet deep. But thick mulch 6-8," allows gardeners to manipulate the area just enough to help our plants along.
Mulch should be materials that drain & dry quickly like straw, hay, chopped corn stalks or pine needles. Leaves stay wet and compact. If you must use leaves, a least put a thin layer of 2" of the other materials first, so the leaves don't have direct contact.
It's not too late to cover plants and we can't always count on snow to 'cover' them for us. And yes, I would still give the evergreens and perennials a shot of water, you'll thank me in the spring!