What To Do With Chrysanthemums in September for a Fabulous Fall Display

Whether you're planning a fall porch display of pots, or want your garden chrysanthemums to look their best, there are a few things you can do this month and next to boost your blooms.

Loved by many, this so-called queen of fall flowers comes into its own this season. Tough and resilient, with an array of vibrant colors and petal shapes, mums love the crisper, shorter days. Yet, they will still need some attention to look their best.

If you know how to grow chrysanthemums, or care for the potted varieties, like this beautiful Matchsticks chrysanthemum plant from Burpee, they will reward you with a spectacular show. Here's what gardening experts suggest to keep mums looking fabulous this fall.

1. Allow Plenty of Sunshine

When planning your outdoor fall décor ideas, carefully consider where to place your pots, so they can thrive – and be enjoyed. Chrysanthemums require at least six hours of sunshine per day to flourish, whether they are planted in the ground or in containers.

'If you're planting perennial mums, choose a location with good air circulation and plenty of autumn sunshine,' says horticulturalist, Sharon Murphy, founder, Gardening with Sharon.

'Avoid crowded areas where foliage stays damp for long periods because that is a perfect breeding ground for disease.

'Place nursery-grown potted chrysanthemums in sunny areas of a deck, patio, or porch where they will get their fill of sunshine.'

This gorgeous Garden Mums Quart Pot offer from Plant Addicts allows you to mix and match colors and cultivars to create a distinct display.

Sharon Murphy

Sharon Murphy is a passionate horticulturist with over 30 years of gardening and greenhouse growing experience in Alberta, Canada and on the tropical island of St. Thomas in the US Virgin Islands. A third generation greenhouse grower, Sharon has a specialty in annuals and perennials, and also worked as greenhouse retail and marketing strategist. 

2. Water Plants Deeply

Unless you have had a significant amount of rainfall in your region, it's highly likely your mums will need watering. In most areas the ground will still be dry and pots will certainly need to be checked regularly for moisture levels.

'Keep watering your mums deeply once or twice a week for as as long as the flowers are still blooming,' says Jessica Hall, co-founder, Harmony Harvest Farm. 'Maintaining consistent moisture will prevent drought stress. Mums are very, very thirsty but they don't like wet feet, so water when the top two inches of soil is dry.'

This steel watering can from Ace Hardware has a retro style and holds two gallons.

Sharon explains that a good soaking less often is much better than frequent little sprinkles, especially for in-the-ground mums.

'Chrysanthemums have fairly shallow root systems, and flowering plants can dry out surprisingly quickly,' says Sharon. 'Soaking encourages the roots to grow deeper and helps prevent the plant from drying out between waterings.

'Although, avoid spilling water over the foliage and flowers to prevent disease development.'

Like other plants, potted chrysanthemums tend to dry out much faster than those growing in the ground. 'This is because their roots may be pot bound and are confined to a relatively small amount of soil,' adds Sharon. 'Give them a thorough drink of water as soon as you get them home but don't let containers sit in water-soaked drip trays.'

Tim Pollak, Manager, Plant Production at Chicago Botanic Garden points out that if plants are allowed to dry out, the flowers and future buds may not fully recover.

'Don't rely on rain, as the plants are full, and create an umbrella effect over the root zones,' says Tim. 'Water thoroughly as often as required.

'If planting in containers, use a larger container than the plants came in. This will help with keeping them moist and preventing them from drying quickly.

'Always make sure the containers have drain holes before planting, as this will prevent them from staying too wet and developing root diseases.'

If you're yet to buy your potted mums, this Mammoth Daisy Red from Burpee has bold red petals and bright yellow stamens for a vibrant show.

Jessica Hall

Along with her sister and mother, Jessica Hall is co-owner of Harmony Harvest Farm, growers of chrysanthemums. With over 80% of the flowers grown in the US being imported, the team are passionate about giving floral professionals access to seasonally rich, American-grown flowers. Based in Virginia, the farm specializes in weddings and bulk flower sales to local florists. 

Tim Pollak

Tim Pollak is Manager of Plant Production at the Chicago Botanic Garden, where 2.7 million plants make up the permanent collection. His work includes growing over 250,000 plants a year and buying all plants for seasonal annual displays, containers, hanging baskets, and specialty plant displays. He also assists with the seasonal (spring, summer, and fall) annual design and the plant selection process. 

 

3. Feed Mindfully

Mums planted in flower beds may require a light feed this month, but go easy and choose a low nitrogen formula.

'You can feed the plants once or twice during the fall,' says Tim. 'If planting in the ground, this will also promote root growth and help them potentially survive through the winter.'

'Switching your fertilizer to a bloom booster formulation with lower nitrogen and higher phosphorus and potassium will encourage flower blooming on your mums rather than vegetative growth,' says Jessica.

This flower fertilizer from Lowe's should do the trick. However, stop feeding them as soon your mums start flowering.

'Too much nitrogen late in the season can encourage soft, leafy growth when what we really want is flowers,' says Sharon. 'Avoid heavy feeding in late summer and fall. Also, flowering potted Chrysanthemums do not require additional fertilizer.'

4. Deadhead & Disbud

Deadheading chrysanthemums may reveal unopened buds below, and will keep the plant tidy. So whichever varieties you're growing, it's worth removing spent flowers.

'In the garden, simply snip off faded flower heads just above a healthy set of leaves or branching point,' says Sharon. 'Don't worry about removing every single faded bloom in a large stand of plants, because a quick tidy-up every few days is enough to keep everything looking fresh.

'There's no need to be overly aggressive either; you're removing the finished flowers, not reshaping the plant.'

'If you want larger, show-quality flowers, you can also 'disbud' by removing the side buds so the central bloom grows larger,' adds Jessica.

These Fiskars Micro-Tip Snips from Ace Hardware have soft grip handles for comfort and stainless steel blades for clean cuts.

'Potted mums bloom once and then they are done,' says Tim. 'Though removing older faded flowers can keep the plants looking good through the fall.'

5. Protect Your Mums From Frost

Chrysanthemums like cooler weather conditions, but the flowers are much more vulnerable to frost than the plant itself. So keep an eye on the forecast and have a frost cloth at the ready.

'A light frost doesn't necessarily mean the end of your perennial chrysanthemums,' says Sharon. 'Protecting the plants from repeated frosts can buy you considerably more flowering time.'

'When a frost warning is issued, cover in-the-ground plants with a lightweight frost cloth, old sheet, or similar breathable material resting on stakes or supports before temperatures drop.'

These 36" bamboo stakes from Ace Hardware are a good height for most mums.

'The covering can be removed once temperatures rise above freezing the following morning,' says Sharon.

'Potted chrysanthemums do best when they are protected from all extremes; hot, cold, dry, or wet weather. Gather them into a sheltered spot when there's a frost warning and return them to their sunny spot once the weather warms up the next day.

'As the weather becomes consistently cold, the nursery-grown container eventually wears down, flowers less, and finishes, and that's perfectly normal.'

6. Buy Potted Plants in Bud

To extend a potted Chrysanthemum display, it's best to buy your plants before they have had a chance to fully bloom.

'Chrysanthemums are usually hardy in zones 5-9, so in colder zones, the nursery-grown pots are definitely the mode of choice,' says Sharon. 'Choose plants with mostly unopened buds amongst a few open flowers and remove the finished flowers to encourage unopened buds to release.'

Tim also suggests looking for plants that are in bud, and just beginning to show flower color to get the longest bloom period out of potted mums.

'At this point, the plants are already fully grown and won’t get any larger,' says Tim. 'Most stores bring fresh plants every week, so try to purchase the freshest plants, and stay away from the older or discounted plants.'

Shop Outdoor Planters

With chrysanthemums, the choice of colors and cultivars is vast. From small daisy-like flowers to big blousy blooms, in soft or strong shades, this plant allows you to flex your creativity for a fabulous fall display.

'Chrysanthemums don't ask for much, but they reward a little attention with weeks of colour when many other garden plants are calling it quits,' says Sharon. 'Keep the roots evenly moist, deadhead regularly, give them plenty of sun, and protect the flowers when frost threatens.

'With a little care, you can keep that burst of autumn colour going long after the first cool nights arrive.'

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