Planting a potted Chrysanthemum from inside to outside

(Question)

Hi there. I was given a yellow Chrysanthemum plant as a gift several weeks ago. It is doing very well and growing very big. I wondered if I could plant it outside in my garden or if it needed to be repotted in a larger planter to be kept inside. My preference is to move it outdoors. I live in Toronto Canada so I am not sure if this is good idea. I don’t know if it needs sun or shade, what type of soil I can use outside (to mix in the garden…potting soil? garden soil). Also, is it the type of plant that, if planted outdoors, will come back next year? It is really pretty so I would like to keep it.

(Answer)

Congratulations on getting your Chrysanthemum to grow even bigger. This is an interesting question because of the timing of your plant’s bloom.  Mums normally bloom for a few weeks in the fall.  This means your gift was “forced” to send out blooms at a time it doesn’t naturally give flowers. I encourage you to give your chrysanthemum a chance to become “normal.” You can cut it down to about three or four inches, take it out of the pot and plant it in the soil now.  For optimal growth and flowering, mums need at least 5 hours of sunlight during the growing season. Good air circulation is necessary, so give it at least 12-15 inches on all sides. They need adequate watering in well draining soil as they don’t like having their roots wet, so choose your site carefully with these conditions in mind. Add a layer of compost or well rotted sheep manure which will give the plant some nutrients. It is likely pot-bound by now, meaning it has used up all the goodness in the soilless mix. You can also feed with a(n organic) 20-20-20 fertilizer solution every couple of weeks while the plant is vegetatively growing, switching to a 10-20-20 strength when the plant begins to flower.  Fertilizer would not be necessary in its second year, if it survives. Chrysanthemums are herbaceous perennials which means they appear to die back during the winter but regrow again the following spring.   There are many varieties of mums; we cannot assume you have a cultivar that will survive in Toronto’s hardiness Zone, but you can hope for the best.   If you like to leave something for the birds and creatures, you can leave the flowers through the winter.  If you prefer a clean tidy winter garden, cut down the foliage after it has been killed back by a hard frost or prolonged cold weather.  In the spring, when you see new growth, cut back any dead material and repeat.  Always remember to give your soil some help in the form of manure or compost in the spring or fall. Happy experimenting.