Planting Fall Mums – Tips & Suggestions
Since mums bloom late in the season, they are nondescript, though not unattractive, in the border until blooming time. They are best planted next to early bloomers. As these spring blooming flowers fade, the mums will fill in and hide their unattractive fading foliage. Mums are OUTDOOR Plants!
Mums make a wonderful impact in containers, but when planted in mixed borders, they will end your garden season with a bang when paired with other late season bloomers such as sedum, goldenrod, Russian sage, asters, gaillardia and the changing foliage of ornamental grasses.
For mums to be truly hardy, they need time to become established in the ground. Ideally, they are best planted in the spring and allowed to grow in place all season. Unfortunately, we do not offer mums in the springtime so… when planting mums in the fall, it is best to plant them before they start flowering in late August or early September. Planting them before or during bud stage ensures that their energy is not completely going to their flowers yet.
When planting your mums, also consider planting them in a somewhat protected location where they will not be exposed to winter winds that can decrease their chances of surviving the winter.
Sunlight
Chrysanthemums are sun-loving plants. Although they technically require only 6 hours of sunlight each day, the more light they receive, the better their growth, bloom and hardiness.
Mums bloom due to their photoperiodic nature which means they bloom in response to the shorter days and longer nights. When the plant senses a change in the length of darkness in late summer, it begins to set buds. Planting near artificial lights, such as security lights or porch lights, can alter the bloom time of your mums.
The mums you see early in July and August at the big box stores have been forced to bloom early. They will not last into our normal fall season and give you the wonderful colors…We grow our mums to be natural season; they will bloom earlier or later depending on how hot/cool it was when they set their blooms during the growing phase and their blooms will naturally open faster or slower depending on our temperatures during the fall. Bottom line – we don’t trick them into blooming!
Soil
Mums can survive in most soils, but they thrive in well-draining soil with consistent moisture. Growing mums in hard, dry soil prevents the roots from becoming well established, while wet, boggy soil drowns the roots. Finding the middle ground is key.
If you’ve planted other perennials, then you already know how to plant mums. To create a good soil for your mums, work your soil to a depth of 8 to 12 inches. Mix in 2 to 4 inches of organic material, such as compost, peat moss or some of the older soil from your spring pots. The perfect soil texture can be tested by taking a handful and squeezing. When you open your hand, the soil shouldn’t clump or quickly fall apart. It should simply crumble. Mums like a soil pH slightly on the acidic side.
Spacing It can be tempting to plant mums closely together. Planted mums will reach up to 3 feet in height and width. Like many perennials, mums will often become larger each year. Even if your flower bed looks a bit bare when you first plant your mums, in time it will fill in.
Spacing mums properly is essential for plant health. Plants that are too crowded compete for nutrients, have root system issues, attract pests and suffer from disease.
Watering Planted Mums
It is very important that mums establish a good root system. The deeper the roots, the more likely the plant will survive very hard freezes and even drought conditions. To encourage deep root growth, water your soil so that it is wet down to a depth of 6 to 8 inches. Mums do not like to get dry. Insert a stick into the soil and see if it is damp at that depth. Soil should remain moist, but not soggy. Soggy soil can cause root rot and other diseases. It can be difficult for a mum to bounce back once it has been over watered.
Once the ground cools, stop watering your mums. This can be anywhere from late September to early October. Cover the soil around your plants with a 2- or 3-inch layer of mulch. This will help the soil retain moisture without it becoming very saturated. It will also protect the plant's roots from hard winter freezes.
If you are using your mums for decoration in pots on your porch, you can still get them into the ground. Will they survive? Maybe? Especially if you do continue to water into November – especially if we have a dry fall. Often, our fall weather is mild until late November, early December.
Temperature and Humidity
If high temperatures occur, particularly at nighttime, it can cause the plant to flower later than it normally would. Heat delay can cause irregularly formed flower buds, erratic flowering, deformation of the plant’s crown and other developmental issues.
Cool temperatures don't bother mums. In fact, chilly weather intensifies colors and keeps blossoms looking fresh until a hard, killing frost drops the curtain on the gardening year.
Tuck Them in for Winter
As one of their nicknames "hardy mums" suggests, they can handle cool temperatures. The key to winter survival is a consistent soil temperature. Frequent freezing and thawing cycles damage the roots and confuse the plant. Adding a thick layer of mulch can help maintain an even soil temperature throughout winter by providing extra plant protection.
First, leave the foliage on the plants until after a killing frost and the foliage turns brown. Cut them back after the foliage has turned brown to 4-6” above the soil line.
Another line of thinking: Research reveals allowing the mum to die back naturally over the winter produces a stronger plant. Simply clean up the dead stems and foliage in the spring.
Unfortunately, for most of us…we forget the next step of mulching and protecting the roots and as mums are shallow rooted plants, the extra foliage on the top of the plant adds weight and more surface space for the snow and frost to tip the roots out of the ground – Mums don’t like their hiney’s exposed to the cold! They will die.
One more thought on leaving the foliage until the spring… many pollinators will use the foliage as a place to lay their eggs and then upon hatching in the spring, the foliage will provide protection from predators.
Spread at least 4 to 6 inches of mulch or compost under your mums as soon as the surface of your soil begins to harden and the thermostat begins to dip into the 20s.
Fertilizer
It is important to provide nitrogen and potassium to mums during their vegetative/growing phase. Feed the plants before flower buds form to promote healthy roots, bud development, and a vigorous plant. Start a feeding cycle in April or May.
You can get a time-released fertilizer which feeds the plants for about three months. We encourage you to not follow the directions
