When To Plant Mums In The Ground

Knowing when to plant mums in the ground is the single most important factor for getting those stunning, full blooms you see in garden centers. Get the timing wrong, and you might end up with a plant that struggles to survive the winter or fails to flower its best. This guide will walk you through the ideal planting windows, the reasons behind them, and the simple steps to ensure your mums thrive for seasons to come.

This core question has two answers, depending on your goal. Are you treating mums as a stunning annual display for fall color? Or do you want them to return as hardy perennials, growing larger and more beautiful each year? The calender date changes based on your choice.

For perennial success, the golden rule is to get them into the ground in the spring. This gives the plant’s roots an entire growing season to establish themselves firmly in your garden soil. A well-established root system is what allows the plant to anchor itself, access water and nutrients efficiently, and most importantly, survive freezing winter temperatures. Think of it as giving your mums a long runway to prepare for the tough season ahead.

If you plant in the fall, the plant is putting all its energy into blooming, not root growth. It simply won’t have time to get settled before the ground freezes. This often leads to the plant heaving out of the soil during freeze-thaw cycles, which is usually fatal.

The Ideal Spring Planting Window

Aim to plant your mums after the last hard frost has passed in your area. The soil should be workable and beginning to warm up. For most regions, this falls between late April and early June. You can check your local frost dates online for a more precise target.

Why is spring so much better? Here’s what happens:

The plant focuses on vegetative growth, producing lots of leaves and stems.
Roots expand deep and wide, creating a strong network.
The established plant can better handle summer heat and drought.
When fall arrives, it redirects its robust energy into producing massive amounts of flowers.

The Reality of Fall Planting

Let’s be honest: most of us buy mums in the fall when they are in full, glorious bloom. If you choose to plant them at this time, manage your expectations. Treat them as annuals for fantastic seasonal color.

If you hope they might return, you can take a few extra steps. Plant them the moment you bring them home, don’t let them sit in pots. Choose a sheltered location and provide excellent care. But understand, their survival is not guaranteed. The key is to get them in the ground at least six weeks before your first expected hard frost. This gives them a tiny bit of time for some root development.

Choosing the Right Mums for Your Garden

Not all mums are created equal when it comes to hardiness. When shopping, especially in spring, look for labels that say “hardy garden mum” or list a specific USDA hardiness zone (usually zones 5-9). Florist mums, often sold as gift plants, are typically bred for a single showy display and are less likely to be winter-hardy.

Understanding “Photoperiod” and Bloom Time

Mums are what we call “short-day” plants. This means they begin to form flower buds when the nights get longer in late summer. This is why they naturally bloom in the fall. When you buy a mum in bloom in spring, it has been artificially manipulated in a greenhouse. Planting it in your garden will reset its clock to the natural seasons.

Step-by-Step Guide to Planting Mums

Follow these steps for the best results, whether planting in spring or fall.

Pick the Perfect Spot: Mums need at least 6 hours of direct sunlight daily. Less sun leads to weak, leggy growth and few flowers. Ensure the location has excellent drainage; they hate soggy, wet feet.
Prepare the Soil: Work the soil to a depth of about 8-12 inches. Mix in several inches of compost or well-rotted manure. This improves drainage, adds nutrients, and creates a welcoming environment for roots.
Plant at the Right Depth: Dig a hole twice as wide as the root ball but no deeper. The top of the root ball should be level with the surrounding soil surface. Planting too deep can cause stem rot.
Space Them Out: Place plants 18-24 inches apart. Good air circulation helps prevent foliar diseases like powdery mildew.
Water Deeply: After planting, water thoroughly to settle the soil around the roots. Keep the soil consistently moist (but not waterlogged) for the first few weeks as they establish.
Add Mulch: Apply a 2-3 inch layer of shredded bark or other organic mulch around the plants. This helps retain moisture, suppress weeds, and insulate the roots from temperature swings.

Essential Care for Optimal Blooms

Planting is just the beginning. A little ongoing care makes a huge difference in flower power.

Watering Wisely

Mums have shallow roots systems that can dry out quickly. Provide about 1 inch of water per week. Water at the base of the plant, not overhead, to keep leaves dry and prevent disease. During hot, dry spells, they may need more frequent watering.

Pinching for a Bushier Plant

This is the secret trick for getting a mound-shaped plant covered in hundreds of blooms, instead of a tall, spindly one with few flowers. Starting in late spring to early summer, use your fingers or pruners to pinch off about 1 inch of new growth from the tip of each stem.

Do this every 2-3 weeks until around mid-July.
Each pinch encourages the stem to branch out, creating a denseter plant.
Stop pinching by mid-July to allow flower buds to form for fall.

Fertilizing for Strength

Feed your mums in the early growing season to support all that new growth. Use a balanced, all-purpose fertilizer (like a 5-10-5) in late spring and again in early summer. Avoid fertilizing after late July, as this can promote tender new growth that will be vulnerable to frost.

Preparing Mums for Winter

If you planted in spring and want your mums to return, winter preparation is crucial. After the foliage turns brown following a hard frost, you can cut the stems back to about 2 inches above the ground. Do not cut them back while they are still green.

Add an extra layer of mulch (like straw or shredded leaves) over the crown of the plant after the ground has frozen. This insulation prevents the freeze-thaw cycles that can heave plants out of the ground. In early spring, gently pull this extra mulch back as new growth appears.

Common Problems and Simple Solutions

Leggy Growth, Few Flowers: This is almost always caused by insufficient sunlight. Move them to a sunnier spot next season.
Brown or Spotted Leaves: Could be a sign of fungal disease from overhead watering or poor air circulation. Water at the base and ensure proper spacing.
Plant Dies Over Winter: Most often caused by late-season planting, poor drainage, or lack of winter mulch for insulation.
Center of Plant Dies Out: Mums naturally grow outward. Every 2-3 years in the spring, dig them up, divide the healthy outer shoots, and replant to rejuvenate.

FAQ: Your Mum Planting Questions Answered

Q: Can I plant potted mums in the fall?
A: Yes, but for immediate color, not guaranteed perennial growth. For best survival, plant them as early in the fall as possible and provide winter protection.

Q: What month is best for planting mums?
A: For perennial mums, aim for April, May, or early June. For fall-planted annuals, get them in by late September.

Q: How do I get my mums to come back every year?
A: The winning combo is: 1) Plant hardy varieties in the spring. 2) Ensure perfect drainage and full sun. 3) Provide a protective winter mulch after the ground freezes.

Q: Should you water mums everyday?
A: No. Deep watering less frequently is better. Aim for 1 inch per week, adjusting for rain and heat. Check the soil moisture a few inches down.

Q: Why are my mums blooming in the summer?
A: Some early-blooming mum varieties naturally flower in late summer. Also, if you purchased a plant already in bloom in spring, it may take a full year to adjust to your garden’s natural light cycle.

By following these timing and care guidelines, you can enjoy the vibrant, autumnal beauty of mums in your garden. The key takeaway is simple: for a one-season show, plant them whenever you buy them. For a long-term garden friend that expands its display each year, patience and a spring planting are your surest path to success. With the right start, these classic fall flowers will reward you with reliable color when many other plants are fading.