Limelight hydrangea standards are a tree form of the limelight hydrangea shrub. Huge panicle blooms start creamy white & slowly age to a beautiful chartreuse with hints of pink . They are hardy down to zone 3, so typically they don’t need to be protected in the winter months, IF they are planted in the ground. Why is that an important fact? Because shrubs are designated their hardiness based on the rule that they are planted in the ground. I garden in a region of the Midwest that is designated zone 5. We are slammed with the infamous polar vortex almost every winter; I have to make sure my hydrangeas are protected if they are in planters, and not in the ground.
The general rule of thumb is that you can put a plant in a planter as long as its two zones hardier than the zone you garden in.
As mentioned before, the limelight hydrangea is a zone 3-9, so it’s tough enough to withstand temperatures as low as -40°F. In this case, I didn’t need to protect them for the winter. I could have left them in the planter and instead of the plant being hardy down to zone 3, it would be hardy down to zone 5. Which means they would likely survive. However, for the sake of protecting my investment, because these can be very costly versions of the this shrub, I went ahead and overwintered them anyway.
Most people think using burlap alone will suffice in protecting their outdoor shrubs. For example, wrapping your emerald green arborviteas in burlap will help keep them warm and fuzzy over the winter, but again, these evergreens are planted in the ground and therefore burlap is enough. A plant in a pot/planter needs it’s roots protected. When protecting evergreens, shrubs, and plants in a planter, using more heavy duty insulation will have great benefits. That brings me to……..bubble wrap. Along with it’s ability to keep fragile items in storage cushy, it works wonders for trapping heat around the root ball of the plant when wrapped around planters. This keeps the root at a temperature more conducive to the zone it’s designated for.
For this example, I used bubble wrap, a pair of scissors, twine, burlap, and gorilla tape. Bubble wrap was generously wrapped around each planter, and taped down using the gorilla tape. The plastic was positioned to be slightly higher than the edges of the planter to provide a little extra shielding. Then burlap was used to wrap around the bubble wrap, and secured with twine. Making sure the twine is taut, and wrapped around the planter a few times will ensure the burlap doesn’t come apart under the weight of any snow.
Once the weather really begins to cool, I’m going to mulch the top of the soil to keep moisture in. This will also help with insulating the top of of the soil. I will still water these limelight hydrangea standards roughly once or twice every two weeks. Despite it being the dead of winter, soil will still be very much alive, and the plant will still need to be watered to thrive. Only not as often as I would water it in the warmer months.
I hope this post inspired you to plant your favorite shrub in a container. I also hope it gave you the confidence to know that you can very well keep it in that container all year long, if you take the steps listed above to keep it warm and snuggly through the colder winter months.