By Claire WhitakerUpdated November 2026
If you want to recommend the best perennials to plant in May, the goal is usually simple: plants that establish before summer heat, come back reliably year after year, and don’t demand constant attention. May is a transitional month for most gardens. Soil is warming, frost risk is mostly past in many regions, and young plants have a good window to root before the stress of July. The five picks below were chosen by comparing published growth habits, hardiness ranges, bloom timing, brand reputation and common owner feedback patterns. None were grown or tested by the author.
Our top picks at a glance
- 1
TOP CHOICEBest overallEden Brothers All Perennial Wildflower Mixed Seeds for PlantingView on Amazon - 2
TOP CHOICEBest for pollinator gardensBearded Iris Colorful Crop Mix – 3 RhizomesView on Amazon - 3
TOP CHOICEBest for cottage bordersSweet William Seeds Perennial for Planting – Dianthus SeedsView on Amazon - 4
Best for vertical accentsBlue Allium Caeruleum Bulbs – Sky Blue Globe FlowersView on Amazon - 5
Best for late-season colorNew England Aster Heirloom Flower Seeds – Aster Novae-AngliaeView on Amazon
Our Top Picks
| Product | Best for | Key feature |
|---|---|---|
| Eden Brothers All Perennial Wildflower Mixed Seeds | Mixed meadow-style planting | Blend includes lupine and Shasta daisy; spring or fall sowing |
| Bearded Iris Colorful Crop Mix | Drought-tolerant sunny beds | Rhizomes bloom in spring with some fall rebloom |
| Sweet William Seeds Perennial | Cottage-style borders | Fragrant dianthus flowers in a wide color range |
| Blue Allium Caeruleum Bulbs | Vertical accents | Globe-shaped sky-blue flowers on 12–24 inch stems |
| New England Aster Heirloom Seeds | Fall color and pollinators | Purple blooms in late season, native perennial |
Eden Brothers All Perennial Wildflower Mixed Seeds for Planting
Eden Brothers All Perennial Wildflower Mixed Seeds for Planting, 1 oz, Seeds with Lupine, Shasta Daisy | Attracts Pollinators, Plant in Spring or Fall, for Zones 3, 4, 5, 6, 7, 8, 9, 10
Best for: Mixed meadow-style planting with a broad bloom season
This blend suits gardeners who want a loose, naturalistic display rather than a formal bed. It is a practical choice for open areas, borders with room to spread, and yards where pollinator support is a priority.
Key specs If you want more background, see Companion Planting with Peppers: 8 Best Plants and Pairings.
- Package size: 1 oz
- Includes lupine and Shasta daisy
- Listed for planting in spring or fall
- Listed hardiness zones 3 through 10
Pros
- Wide hardiness range listed by the seller
- Mix offers layered height and bloom timing
- Marketed as attractive to pollinators
Cons
- Mixed seeds can vary in germination and first-year bloom
- Requires patience; many wildflower mixes flower in the second season
Bottom line: Best for gardeners who want a natural, pollinator-friendly planting and can accept some variation in results.
Bearded Iris Colorful Crop Mix – 3 Rhizomes
Bearded Iris Colorful Crop Mix – 3 Rhizomes – Spring Flowers, Fall Reblooming, Easy to Grow Drought Tolerant Perennial Plants
Best for: Drought-tolerant sunny beds with reliable spring flowers
Bearded iris is a long-lived perennial that tolerates dry spells once established. It works well for gardeners in sunny spots who want structural foliage and early color.
Key specs
- Quantity: 3 rhizomes
- Bears flowers in spring
- Listed as drought tolerant and easy to grow
Pros
- Established clumps are low-maintenance
- Strong sword-shaped foliage adds interest after bloom
- Good choice for sunny, well-drained soil
Cons
- Rhizomes must sit at or just below the soil surface, which can confuse new planters
- Only three rhizomes means a slow fill-in for larger beds
Bottom line: A solid pick for sunny beds where drainage is good and you want reliable spring color.
Sweet William Seeds Perennial for Planting – Dianthus Seeds
5000+ Sweet William Seeds Perennial for Planting-Dianthus Seeds Sweetness Flower Non-GMO Heirloom for Outdoor Garden Hardy to USDA Zones 3-9
Best for: Cottage-style borders and fragrant cut flowers
Sweet William is a classic dianthus that fits informal borders and rock gardens. The clove-scented flowers are a draw for gardeners who like scent as well as color.
Key specs
- Quantity: approximately 5,000 seeds
- Listed as non-GMO heirloom
- Listed hardiness zones 3 through 9
Pros
- Large seed count stretches a long way
- Fragrant, long-lasting cut flowers
- Tolerates cool spring weather
Cons
- Seeds are slower to bloom than transplants, often in the second year
- Short-lived in heavy, wet soil
Bottom line: Ideal for gardeners who enjoy sowing from seed and want fragrance in a traditional border.
Blue Allium Caeruleum Bulbs – Sky Blue Globe Flowers
Bright blue flower clusters rise 12–24 inches tall for eye-catching accents among perennials and grasses | 10 bulbs 10 Blue Allium Caeruleum Bulbs – Sky Blue Globe Flowers for Planting
Best for: Vertical accents among perennials and grasses
Ornamental alliums add height and a sculptural shape without crowding neighboring plants. They pair well with mounding perennials and ornamental grasses.
Key specs
- Quantity: 10 bulbs
- Listed height: 12–24 inches
- Sky-blue globe flower clusters
Pros
- Distinctive globe-shaped blooms
- Deer and rodent resistance is commonly reported by owners
- Foliage is compact and tidy
Cons
- Bulbs are planted in fall for most climates, so May planting is less typical and may bloom late or not at all in the first year
- Foliage fades after bloom and leaves gaps
Bottom line: Worth considering if you can accept a possibly delayed first bloom; check bulb-planting timing for your zone.
New England Aster Heirloom Flower Seeds – Aster Novae-Angliae
USA Packed, Heirloom, Non-GMO Seeds for Planting, Flower, Purple Fall Blooms, Native Perennial, Cut, Attracts Pollinators 600 New England Aster Heirloom Flower Seeds, Aster Novae-Angliae
Best for: Late-season color and pollinator support
New England aster blooms when many other perennials have finished. It is a strong choice for autumn color and for feeding late-season bees and butterflies.
Key specs
- Quantity: 600 seeds
- Listed as heirloom, non-GMO and native
- Purple fall blooms
Pros
- Native plant with strong pollinator value
- Late-season bloom fills a gap in the garden
- Tolerates a range of soils once established
Cons
- Seed-grown plants take a full season or more to flower
- Tall types may need staking or pinching to stay compact
Bottom line: A strong native choice for gardeners who want fall color and wildlife value and can wait a season for blooms.
Buying Guide
Planting Timing and Your Climate Zone
May planting works best when soil has warmed above about 50°F and nighttime lows stay reliably above frost range. Check your USDA hardiness zone and the average last frost date for your area. In cooler northern zones, May is often ideal for transplants; in warmer southern zones, you may need to plant earlier or water more closely during heat.
Good picks for this: Eden Brothers All Perennial Wildflower Mixed Seeds, Sweet William Seeds Perennial
Seed Versus Divisions or Bulbs
Seeds are inexpensive per plant but slower to bloom. Rhizomes, bulbs and divisions usually flower sooner. Decide whether you can wait one season for flowers before choosing a seed-grown option.
Good picks for this: Bearded Iris Colorful Crop Mix, New England Aster Heirloom Flower Seeds
Sun and Soil Requirements
Most perennials in this list prefer full sun to light shade and well-drained soil. Heavy clay or waterlogged spots cause rot in iris and dianthus. Amend heavy soil with compost and test drainage by filling a hole with water and checking that it empties within a few hours.
Good picks for this: Bearded Iris Colorful Crop Mix, Sweet William Seeds Perennial
Hardiness Range
Check the zone range listed on the product. A wide range, such as zones 3 through 10 for some wildflower blends, gives more flexibility across climates. Still confirm that your summer heat and winter cold fall within what the plant tolerates.
Good picks for this: Eden Brothers All Perennial Wildflower Mixed Seeds, Sweet William Seeds Perennial
Height and Placement
Plan by mature height and spread. Alliums and tall asters should sit behind shorter plants so they do not shade the front of the border. Group plants with similar water and light needs.
Good picks for this: Blue Allium Caeruleum Bulbs, New England Aster Heirloom Flower Seeds
Pollinator and Wildlife Value
If pollinators matter to you, look for native species and single or open-form flowers, which are generally more accessible to bees than heavily doubled blooms. Native asters and wildflower mixes score well here.
Good picks for this: New England Aster Heirloom Flower Seeds, Eden Brothers All Perennial Wildflower Mixed Seeds
Establishment Care in the First Season
Newly planted perennials need consistent moisture for the first several weeks. Water deeply two to three times a week in dry weather, and mulch with 2 to 3 inches of shredded bark or compost to reduce evaporation. Expect slower growth in year one, with fuller plants in year two or three.
Good picks for this: Bearded Iris Colorful Crop Mix, Blue Allium Caeruleum Bulbs
FAQ
Can you plant perennials in May?
Yes. May is a good planting month for many perennials, especially once frost danger has passed in your area. Container-grown plants establish most easily, and seeds should be sown when soil temperatures are suitable for germination.
What is the best time to plant perennial seeds?
Many perennial seeds are sown in fall or early spring so they can go through cold stratification. May sowing is possible in warm climates or for seeds that do not need cold treatment, but check the seed packet for each species.
Will perennials planted in May bloom the same year?
Transplants and divisions often bloom in their first season, while seed-grown perennials commonly flower in year two. Bulbs may take longer if planted outside their normal window.
How deep should I plant bearded iris rhizomes?
Set rhizomes so the top is at or just below the soil surface, with roots spread downward. Burying them too deep is a common reason plants fail to bloom.
How often should I water new perennials?
Water deeply two to three times a week during dry spells for the first few weeks. Once roots are established, most perennials need less frequent watering. Adjust for your soil type and rainfall.
Do these perennials attract pollinators?
Native species such as New England aster and wildflower mixes are generally valued by pollinators. Exact visitor numbers depend on your region and surrounding plantings.
Conclusion
To recommend the best perennials to plant in May, start with your climate and how long you can wait for flowers. The Eden Brothers wildflower mix suits natural, pollinator-focused beds. Bearded iris fits sunny, well-drained spots and offers reliable spring color. Sweet William works well for fragrant cottage borders grown from seed. Blue allium adds vertical interest, though May planting may delay bloom. New England aster is the choice for late-season color and native value. Match the pick to your site, zone and patience, and most gardens will settle into a steady, low-effort display.
Sources
- USDA plant hardiness zone map and zone definitions for choosing perennials by climate (usda.gov)
- University extension guidance on planting, soil preparation and perennial establishment (extension.org)
- Pollinator habitat recommendations, including native plant selection
Related reading
- Are Lily Plants Perennials? 6 Best Picks Compared for 2026
- Are Lantana Plants Perennials? 5 Best Picks Compared for 2026
- When and How to Divide Perennial Plants Successfully
- What Does Perennials Plants Mean? A Plain-English Guide
- Types of Perennials Flowers: 7 Best Picks for Every Garden (2026)
About Claire Whitaker
Claire Whitaker is part of our editorial team and reviews and edits our plant care Q&A guides, checking product details against manufacturer specifications and owner feedback.
