Mums, cool loving annuals & perennials will take temperatures down to 28’F, but if you want to save any plants you can do one of the following:
Many people use mums to decorate their homes in the fall by leaving them in pots and treating as an annual for decoration. The best time to purchase mums is after temperatures have started to drop (preferably under 79’F highs), which usually means after Labor Day to the end of September. If mums are just starting to show color, lots of buds with only a few open blooms, you will get the longest time of enjoyment (at least 4-6 weeks). Below is a care sheet with the details on fertilizing, etc.
“Decorative” mums have been bred to have unique colors & pom-pom flowers, so they often are not as hardy and able to survive our winters. The Mammoth mums are the only truly perennial mum in our area, but still need to be planted by early September, so that they have enough time to root out before frost. Putting 4” of hardwood mulch over the plant after the ground freezes may help provide more winter protection to the tender roots.
Preparing for Winter
Perennials: The biggest cause of perennials not surviving the winter is that they die from crown rots because the soil around the crown (where the base of the plant meets the soil) is too wet in the fall. If you have an area that perennials routinely don’t come back it may be because of moisture and means you either need to build the area up with more soil or choose plants that prefer wet conditions (like Joe-Pye Weed/ Eupatorium).
Two more things –
1. DON’T CUT BACK THE FOLIAGE! The best is to let perennials die back after frost, so that the plant can take all the energy back from the dieing foliage into the roots. This also provides a little mulching or winter protection for the plant against winter cold. Next spring when the tulips start to come up, then cut or pull away all of the old foliage so the new shoots can get light.
2. DON’T MULCH OVER THE PLANTS UNTIL THE GROUND IS FROZEN! Putting shredded wood mulch over plants can give them more protection from the harsh winter temps, and for some plants like Hibiscus it’s almost necessary. But if you mulch over the plants before the ground freezes, it’s very possible the plant can suffocate and die, particularly if we get an unexpected warm spell. In the same reasoning, be sure to pull the mulch away as the tulips start to come up in spring.
Deer don’t only damage plants in the spring/summer, but can also attack trees/shrubs during the winter when they can’t find anything else to eat. If you’ve had problems in the past, many customers swear by Plantskydd for the longest lasting spray even after rain. Click here for more tips on applying Plantskydd.
By mid November you’ll want to clean up the pond of all leaves and debris from plants. Hardy water lilies & zone 4 hardy plants like iris can be cut back and put in the bottom of the pond (as far away from ice as possible), while more tropical plants, like lotus & tropical lilies will need to be brought into a garage or basement for dormancy for the winter. Floating plants like Water lettuce & hyacinths are nearly impossible to keep alive in the winter (even for us in a greenhouse), so pull them from the pond and plan to replace next spring. Click here for video on shutting down your pond for the winter.
Below are additional care sheets for more specific recommendations: