Back in July, I planted four Mohican Viburnums in Triple Mix in 23” x 27”planters on my terrace, which is on the 21st floor and faces west and north in Toronto, at Bloor/Sherbourne. The planters are along the east partition with the neighbour.
After so many months, the plants have not grown one millimetre. If I had planted plastic viburnums, the results would have been identical.
The plants are still green but some of the leaves have curled downwards. Picture attached.
If they survive the winter, any chance that they will they start growing next spring?
Thank you for your input.
Thank you for this interesting question about growing Mohican Viburnums, (Viburnum Lantana ‘Mohican’) in pots on your balcony. Sadly, I can see from the enclosed photo that you certainly do not have very happy plants. There could be a number of possible reasons for this. You have a unique environment being more than 20 floors up, and facing west and north. You say the plants are on the eastern side next to the divide with your neighbours. My immediate concern is that it is very windy, and potentially cold, on your deck in this downtown corridor, and that your plants are not receiving enough light.
However, you should be receiving some afternoon sun. Are your shrubs getting about four hours of sun a day? According to Mohican Wayfaring (Viburnum lantana ‘Mohican’) at Millcreek Nursery Ltd, they can be grown in either full sun to partial shade. Cold should also not be an issue with your Mohican Viburnums. They are very hardy shrubs and according to the above website they are hardy to Zone 3a in Ontario, which is great news. Since you live in the heart of Toronto, you are in zone 6. Even taking into account how high up you are, a shrub that is three zones lower should work.
Exploring other possible problems: you mention you used triple mix in the planters rather than potting soil. Therefore, it is possible that you have an issue with water retention. Perhaps in the spring, you could repot the plants with a good potting soil. Also, the photo shows the shrubs are planted quite deep. Plants should be planted so that the soil comes to the division line between roots and branches – no deeper. When you repot your plants, make sure you do not plant them too deeply.
In general, many potted plants have difficulty surviving outside in our winters on decks. The Toronto north-west wind and low temperatures can be very harsh, including large temperature fluctuations. Plants often do not receive enough moisture to survive. The guideline for winter care of potted plants is: find a sheltered spot for them where the temperature does not fluctuate, keep watering them up until there is a deep frost, and if you want to cover in burlap, make sure the burlap is not touching the leaves and branches. More guidelines can be found in a previous posting from the Toronto Master Gardeners, and we do have a Guideline about growing plants on balconies.
Should you wish to add more plants to your balcony, there are some suggestions for plants that will thrive on your NW balcony in this previous post from the Toronto Master Gardeners.