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Why Are My Mums Not Blooming? (5 Common Causes)

Why Are My Mums Not Blooming? (5 Common Causes)

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Few flowers evoke the spirit of autumn like Chrysanthemums or, as we simply call them mums dance throughout fall displaying domes of vibrant blooms in gorgeous jewel-tone colors.

As fall symbols, mums start to bloom during the late summer through fall, making them perfect “filler flowers” that welcome a splash of color in those empty spots after the summer flowers fade. Mums generally bloom profusely, so there is a viable reason if they aren’t flowering.

Mums stop blooming if you plant them in spots offering less than six hours of direct sunlight. More so, underwatering or soggy soil can cause pests, diseases, and root rot that inhibit flowers growth. Lastly, forgetting to pinch mums in spring can also impact the significance of the blooms.

Garden mums are hardy, fast-growing herbaceous perennials that typically produce flowers during their first growing season from early September to mid-October. However, if cared for incorrectly, the unpreferable conditions can cause these jewels to seize their vibrant blooms altogether.

So, let’s find out what’s the culprit behind your mum’s not blooming.

Why Are My Mums Not Blooming?

It’s pretty obscure when our reliable autumn jewels do not showcase their gorgeous and vibrant domes during the fall. But, thanks to their hardy nature and easy-care requirements, there has to be a reason why these trouble-free flowers lack their distinctive blooms.

The most common reasons that prevent garden mums from blooming include:

  • Incorrect lighting
  • Incorrect watering
  • Waterlogged soil
  • Pests and diseases
  • Forgetting to pinch them after blooming

1 – Faulty Lighting

Chrysanthemums in Partial Sun

Garden mums typically thrive in full sunlight, but they tolerate a bit of shade. However, although they can handle partial shade, the more sun exposure you provide, the more profusely your mums will bloom.

Therefore, aim to place your mums in a spot offering at least six hours of bright direct sunlight to ensure that they stay healthy and continue blooming.

More so, garden mums are “photoperiodic” plants, meaning that they bloom profusely in response to shorter days and longer evenings. The mums set buds by responding to “day length” or light exposure.

So, you’ll want to avoid exposing your garden mums to bright nighttime lightings like a patio or window as the artificial lighting can wreak havoc with the plant’s blooming cycle.

2 – Incorrect Watering

Garden mums enjoy evenly moist soil; they require around one inch of watering weekly during their growing season (late summer through fall).

Moreover, mums enjoy extra watering once the flower buds mature and open. So, you’ll want to ensure that soil never dried out entirely as underwatering can cause the flowers to drop and fall off.

While mums enjoy a lot of water, overwatering your mums can also impact their blooms. Overwatering can cause soggy soil, which leads to root rot, pests, and diseases that inhibit flowering.

3 – Waterlogged Soil

Rain Drops on Chrysanthemums

While mums handle various soil types, they thrive best in rich, slightly acidic soil with sharp drainage. Conversely, poor drainage can cause the plants to rot and stop flowering as they sit in standing water.

So, to ensure that your mums stay healthy and continue blooming, ensure that you steer clear from overly dense and clay-like soil. Instead, plant them in a potting mixture or soil with ample drainage that will help to prevent rot.

More so, if you plant your garden mums in pots, ensure that the containers have proper drainage holes to prevent the plants from sitting in waterlogged soil.

4 – Pests and Diseases

Garden mums are susceptible to various common pests and diseases that can disfigure and impact their blooms if they are not treated soon enough. The primary signs of these problems typically showcase on the mums’ leaves or buds.

While mums are at their very best during the fall, the weather is cool and wet, inviting mold spores or fungal diseases. Consider using an antifungal spray to treat the plant. More so, remove the infected stems to prevent the fungus from spreading.

Then, the most common diseases that affect mums include leaf spot, botrytis, rust, powdery mildew, and stem and root rot. At the same time, the insects that like bothering mums range from aphids, thrips, lace bugs, and leaf miners.

If your garden mums’ flower buds turn brown, treat the plant with a Bordeaux mixture, as the infected buds are unlikely to open once the tips go soft and turn brown.

Consider using sulfur applications weekly until the buds display their first signs of color and apply insecticidal soap or oil to treat pests.

Lastly, if your mums’ leaves are wilting and you are confident that it’s not from overwatering, it can be verticillium wilt (a fungus). Unfortunately, the only solution is removing and destroying the infected plant. More so, avoid planting mums in the exact location as they will contract the same soil fungus and stop blooming or die.

5 – Forgetting to Pinch Mums

Pinching Chrysanthemums

Pinching back mums is a practice that will encourage new growth and prolific blooms by forcing side branches to form that develop new buds and flowers. However, it’s critical to pinch them early in the season to allow the plants to create new stems and buds before the frosty weather sets in.

Pinching entails that you remove around two to three inches of the growing tips using your hands or a sterilized pruning shear.

Ideally, pinch back mums in the spring when they reach around 10 inches high or if they are newly purchased, wait two weeks after you plant them to pinch off the branches. Then, pinch them for a second time during summer solstice as the days shorten after the longest day of the year.

Please note that pinching your mums after July will only remove the buds and reduce blooming. So, wait for them to flower, and once the flowers wilt, chop the dead heads off to encourage your mums to continue flowering for longer.

Final Thoughts

Preluding the change in seasons, Chrysanthemums burst joyful blooms from late summer through fall. So, when your garden mums aren’t flowering, the primary culprit tends to be issues concerning lighting, water, or soil density. In addition, common pests and diseases weaken the plant, leading to fewer blooms.

More so, pinching your mums encourage them to develop new shoots and buds, increasing their flowers throughout their growing season. So, proper care and maintaining the flowers during the bloom period will encourage your mums to flower profusely.

Before you go: Now is the perfect time to start tracking your gardening progress, and I created a garden journal to do exactly that. Click the image below to see it in action and to get your own copy.

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