It’s time to move on to the next season for your decorative outdoor pots. If you missed the briefly warm mid-March window of opportunity to remove your evergreen boughs, you will need to either cut the boughs to the frozen soil level and remove the cut stems under the soil at a later date or pour boiling water to ease the stems out of the soil. If possible, moving the containers into a garage (near an interior wall where it is warmer) or into the house will speed up the thawing process.
If you can thaw the soil, the only décor you can safely add in early April is a collection of twigs and sticks. Consider using curly willow, the red dogwood and/or birch from your winter arrangements and fluffy, Spring-like pussy willows. The soil top can be covered with fresh looking woodland moss. A good garden centre will be stocked in all this product. This can be very effective and the only option during the inconsistent early April temperatures.
Once the deep freeze has passed and night time temps flutter around zero or minus one, the moss can be parted and pre sprouted bulbs can be added to the base of the sticks. Favourites include tulips, hyacinths and daffodils. When it looks like the night time temps will be above zero, cold tolerant annuals such as pansies, primula, campanula, English daisies, ranunculus, dusty miller, and alyssum can all be added to the planters.
If a random freezing night occurs and you are unable to bring in the planter, it can be saved by placing a light bed sheet over the arrangement and letting it return to a normal temperature the next morning without exposing it to sunlight (until it has thawed) and without touching the leaves.