FALL BLOOM SUCCESS
Chrysanthemum Growing Guide
Heirloom mums are excellent cut flowers with a long vase life. Their unique forms, colours, and sizes make them an intriguing fall bloom.
They are prolific producers that start blooming as the days get shorter when other flowers fade due to low light levels. Chrysanthemums are perfect if you have a long growing season or can offer them a sheltered growing space through the fall. They tolerate cooler temperatures in my greenhouse, and with occasional nighttime heating bloom beautifully into mid- late November.
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Growing Guide
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Site Selection
Location: Mums will need protection from frost once blooming so choose your planting site with that in mind. Alternatively, you can plant them in pots that you move if weather gets too cold.
Sunlight: Choose a sunny part of the garden or in a greenhouse/tunnel for fall flower production.
Soil: Mums are moderate feeders. Adding some compost and worm castings at planting time is recommended. But additional fertilizing is not necessary if you have good soil.
Spacing: Plant mums 12-24" apart to allow for air circulation and growth. They can be planted as close as 9" for production purposes.
Protection: Consider a location with some protection from strong winds, especially for tall varieties.
Planting Your Chrysanthemum Cuttings
When to Plant:
- After all danger of frost has passed
- Soil temperature should be warming
- In Alberta, typically mid-late May.
Starting Indoors (Recommended):
- Plant cuttings once you receive them in a 4-6” pot
- Use porous potting soil mixed with compost.
- Plant the mum so the root ball is
covered, keeping the foliage above soil level. - The small pots allow you to control their environment and give them time to recover from shipping and establish before planting outdoors. Give them a good drink of water and
set them in a shady area - Environment: Keep your cutting in a cool area (above 7°C) out of hot, direct light until it adapts and strengthens. Progressively add more light after a couple of days and keep the soil moist but not soggy.
After Frost:
Once the threat of frost has passed, you can harden your plant off and transplant into a sunny garden spot or larger containers with some light soil mixed with compost. Chrysanthemums are moderate feeders so appreciate some well rotted compost added to their planting site.
Staking
Many heirloom chrysanthemums are tall and benefit from support as they grow. Shorter varieties may not require support. Without support they may fall, or bend creating whimsical stems that may be undesirable.
When to Stake:
Install stakes at planting time or use tomato cages to avoid damaging roots later. If planting in pots, add a tomato cage as well to provide support as they grow.
How to Stake:
Use sturdy stakes or supports and tie plants with soft twine as they grow. For multiple plants, consider using t-posts with horizontal support lines.
Watering
Young Plants:
Chrysanthemums are reasonably forgiving in this department. Just make sure you don't over or underwater young plants as they are getting established. Every 4-7 days depending on conditions.
Established Plants:
- I generally water mine twice a week in the greenhouse. They have somewhat shallow roots so can be watered a little more frequent than other plants. Watch for dropping leaves of thirsty plants. Once you get accustomed to them, you can tell just by looking at them if they are thirsty. They will perk right back up after a good watering!
Taking Cuttings
Propagation:
Mums grow easily from cuttings.
Cuttings can be taken until June so your cuttings have sufficient time to develop before blooming.
- Once your plant is established you can cut off the top of tall shoots, or cut smaller sprigs coming up from the soil
- Cut the matured stems in 2-3” sections.
- Remove bottom leaves leaving 1-3 leaves on top of the stem.
- Place the cuttings into new potting soil. Bury approx 1" deep so you are covering an old leaf nod where you removed the leaves.
- Place the cuttings in a shady area and mist them 2-3x daily (or keep a humidity dome on them for a week, misting occasionally).
- Don't over water the soil as the cutting will rot
- After 1-2 weeks, the cutting will develop roots and can be moved to a
sunnier area and watering can be reduced. - Allow the cutting to fully root for around 6 weeks before transplanting outdoors.
Ongoing Care
Disbudding: If you want a larger, showier blooms, remove the side buds off of a stem to allow more energy to be put into the main bloom. This is necessary for competitive showing of chrysanthemums. This is not necessary for small blooming varieties.
Deadheading: Remove spent blooms regularly to encourage more flowers.
Pinching: For bushier plants with more blooms, pinch the main stem to half its height when plants are 6-9" tall (optional, I do not always do this). Plants can be cut back as late as early June for most regions. Pinching encourages side branches and limits unruly, excessively tall plants.
The trimmed piece of the plant can be turned into more cuttings if you are early enough in the season. Keep in mind it will take 4-6 weeks for cuttings to root and mature.
Pest Management: Watch for aphids. Use fans or use organic controls as needed. We also love purchasing beneficial insects from "The Bug Lady" online.
Disease Prevention: Ensure good air circulation to prevent powdery mildew.
Overwintering
Option 1 - Treat as Annual:
Allow frost to kill plants and compost. They can overwinter in zone 7- 8
Option 2 - Store for Next Year:
- Chrysanthemums cannot handle the deep freeze of winter.
- But you can wait until frost hits your plants before digging them up. This will help them go dormant. I cut back foliage to just an inch or two (up to 3-4") above soil level as it helps clean up the plant.
- You can also dig them up before frost hits them.
- You do not have to dig up the whole root ball, but just a portion.
- Store them in pots over the winter in a space that wont freeze. eg. partially heated garage or cool basement. They can be in a dark, dormant space here.
- Check them once a month and if the top 2" of soil is dry then water. Let them dry out between watering as rot can occur in this dormant state. Minimum watering
- Take the plants out in spring if you are taking cuttings. Provide them with moderate light and a space of around 10 degrees celcius or warmer
- Once weather warms you can plant your new cuttings outdoors or replant your mother plant outside.
- We toss the mother plants each season and just use new cuttings. However, you can replant mother plants for another year or so, though in future seasons they may produce less
Troubleshooting
Pests?
Aphids love mums. Keep your plants sprayed down with water to prevent aphids from taking hold. As well, keep a fan on in high production areas, aphids don't reproduce well with breezy conditions. There are also beneficial insects or organic sprays you can purchase at your local greenhouse store. Neem oil is another safe option. Personally, I stick with fans and spraying plants down with water.
Dropping leaves?
You might need to water more. Chrysanthemums have a shallow root system so I water established plants every 3-4 days.
Stunted growth?
Check for pests, improve soil drainage, or add nutrients.
