Mammoth Choice Mix
Lathyrus odoratus
Photo: Penarc · Wikimedia Commons · (CC BY 3.0)
This early flowering variety can withstand heat and drought unusually well. Mix of deep rose, rose pink, salmon, scarlet, white, lavender, medium blue, and deep burgundy produces well into the summer. Can be spelled either as sweet pea or sweetpea. Attracts hummingbirds.
Harvest
75-85d
Days to harvest
Sun
Full sun
Zones
2–11
USDA hardiness
Height
3-8 feet
Planting Timeline
Showing dates for Mammoth Choice Mix in USDA Zone 7
All Zone 7 flower →Zone Map
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Mammoth Choice Mix · Zones 2–11
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
| Zone 1 | May – June | July – August | July – September | — |
| Zone 2 | April – May | June – July | June – August | — |
| Zone 11 | January – January | January – February | January – March | — |
| Zone 12 | January – January | January – February | January – March | — |
| Zone 13 | January – January | January – February | January – March | — |
Succession Planting
Sweet peas quit fast once daytime temperatures push past 80°F, so you've got a finite window and succession planting is how you stretch it. In zone 7, direct sow every 3 weeks starting April 1, with your last sowing no later than mid-May. Anything later and the plants will barely reach full flower before heat shuts them down.
For the longest possible run, sow one batch indoors in February — nick the seeds with a nail file or soak them for 24 hours first, which pushes germination from spotty to 80-90% — then transplant in April and direct sow a second batch outdoors in early April for a staggered flush. Don't bother planning a fall succession unless you're in zone 9 or warmer; in zone 7, the gap between summer heat breaking and first frost is too short for sweet peas to do anything useful.
Complete Growing Guide
Mammoth Choice Mix sweetpeas can be started either indoors or direct sown, depending on your climate and preferences. For indoor sowing, start seeds six to eight weeks before your last spring frost date, then transplant seedlings outdoors after all danger of frost has passed. Direct sowing is equally effective and often preferred since these peas have delicate root systems that transplant well but may benefit from undisturbed growth. Simply sow seeds directly into the garden around the time of your last frost or even a few weeks before, as the seeds can tolerate light frost. The earlier you get them in the ground, the more you'll appreciate their heat and drought tolerance as summer approaches.
Prepare your soil by working in compost or well-rotted manure to ensure good drainage, as sweetpeas dislike waterlogged conditions. Space seeds or seedlings about four to six inches apart and sow them half an inch deep. While Mammoth Choice Mix can eventually reach between three and eight feet tall depending on conditions and support, give each plant adequate room to develop strong root systems early on. Full sun exposure is essential for vigorous growth and abundant flowering throughout the season.
Water regularly during the first four weeks while plants establish themselves, then transition to deeper but less frequent watering as they mature. This variety's exceptional drought tolerance means you can reduce watering frequency once established, though consistent moisture during bloom time encourages continuous flowering. Feed with a balanced fertilizer every three weeks, or switch to a lower-nitrogen formula once flowering begins to promote more blooms rather than excessive foliage.
Mammoth Choice Mix is generally resistant to the common sweetpea challenges, but keep watch for spider mites, which thrive in hot, dry conditions. Despite the variety's heat tolerance, spider mites can still appear during heat waves. Regular misting and good air circulation help prevent infestations. Powdery mildew occasionally affects even heat-tolerant varieties; ensure adequate spacing for airflow and avoid overhead watering in late afternoon.
Provide sturdy trellising or support early, as plants will climb vigorously. Pinch out the growing tip when seedlings reach about six inches tall to encourage bushier, more prolific plants. Deadheading spent flowers is crucial for extending the bloom season well into summer—this variety's ability to flower despite heat makes regular deadheading especially rewarding. Consider succession planting every two weeks in early spring if you want continuous color throughout the season.
The most common mistake gardeners make with Mammoth Choice Mix is assuming heat tolerance means drought tolerance requires zero supplemental water. While this variety handles both conditions better than most sweetpeas, it still needs consistent moisture during its first month and regular watering during flowering for best performance and color intensity.
Harvesting
Mammoth Choice Mix reaches harvest at 75 - 85 days from sowing per Johnny's Selected Seeds. As an annual, harvest continues until frost ends the season.
Type: Legume.
Edibility: Sweet pea fruits are inedible and poisonous to humans.
Storage & Preservation
Fresh sweet pea flowers should be stored upright in a vase with cool water at 35-40°F (refrigerator) or on the counter in cool conditions (60-65°F) away from direct sunlight. They typically last 7-10 days in the refrigerator, 3-5 days at room temperature. For preservation, dry flowers by hanging bundles upside down in a dark, well-ventilated space for 2-3 weeks to retain color. Alternatively, press flowers between sheets of parchment paper under heavy books for 2-4 weeks, or freeze blooms in ice cubes with water for decorative use in beverages.
History & Origin
Mammoth Choice Mix is open-pollinated, meaning seed saved from healthy plants will produce true-to-type offspring. Listed in the Johnny's Selected Seeds catalog.
Origin: Southern Italy, Sicily, Crete
Advantages
- +Exceptional heat and drought tolerance makes it reliable in challenging conditions
- +Stunning color mix includes eight distinct hues creating vibrant garden displays
- +Produces abundant blooms consistently throughout summer months with minimal decline
- +Attracts hummingbirds while offering delightful fragrance for cut flower arrangements
- +Early flowering at 75-85 days provides quick color payoff for gardeners
Considerations
- -Requires sturdy trellising or support due to vigorous climbing vine growth
- -May need deadheading regularly to maintain continuous blooming through season
- -Prefers cool soil despite heat tolerance, limiting planting flexibility in hot regions
- -Susceptible to powdery mildew in humid conditions requiring preventative care measures
Companion Plants
Marigolds — French marigolds (Tagetes patula) specifically — are the most useful neighbor here. Their root secretions deter soil nematodes, and their scent disrupts aphids scouting for a landing spot. Sweet peas attract aphids reliably once they hit full growth, so a row of marigolds at the base of the trellis earns back the space. Nasturtiums work differently: they're a proven aphid trap crop, pulling colonies onto themselves instead of your sweet peas. That concentrates the problem in one spot where you can actually deal with it, rather than chasing aphids across 8 feet of vine.
Zinnias, cosmos, and sweet alyssum attract parasitic wasps and hoverflies that prey on the same aphid and spider mite populations that hit Lathyrus odoratus. Alyssum is particularly easy to tuck in — it tops out around 3-4 inches and won't shade the base of the planting. Lavender doesn't compete hard for water once it's settled in, which fits well alongside sweet peas that want consistent moisture but not standing water; some growers also find it discourages spider mites, though the evidence is mostly observational.
Fennel is the companion to avoid most strictly. It produces allelopathic compounds that suppress neighboring plants, and sweet peas are sensitive enough that stunted growth shows up within a few weeks of close proximity. Pole beans are a different kind of problem — they're aggressive climbers that will compete directly with Mammoth Choice Mix for trellis space, and they don't yield any pest-management benefit in return for that fight.
Plant Together
Marigolds
Repel nematodes, aphids, and other pests while attracting beneficial insects
Nasturtiums
Act as trap crops for aphids and cucumber beetles, attract pollinators
Zinnias
Attract beneficial predatory insects and provide complementary colors
Cosmos
Attract pollinators and beneficial insects while providing structural support
Basil
Repels aphids, mosquitoes, and flies while attracting pollinators
Lavender
Deters pests with aromatic oils and attracts beneficial pollinators
Sweet Alyssum
Attracts hover flies and parasitic wasps that control aphids
Cleome
Attracts hummingbirds and butterflies, provides vertical interest
Keep Apart
Black Walnut Trees
Release juglone toxin that inhibits growth and can kill sunflowers
Fennel
Produces allelopathic compounds that inhibit growth of most garden plants
Pole Beans
Compete for nutrients and sunlight, can climb and damage sunflower stalks
Pests & Disease Resistance
Common Pests
Spider mites, aphids, slugs
Diseases
Powdery mildew, root rot in poorly drained soil
Troubleshooting Mammoth Choice Mix
What you'll see, why it happens, and what to do about it.
White powdery coating on leaves and stems, usually starting on upper leaf surfaces mid-season
Likely Causes
- Powdery mildew (Erysiphe pisi) — a fungal disease that thrives in warm days with cool nights and poor airflow
- Crowded spacing below 6 inches that traps humidity around the foliage
What to Do
- 1.Strip heavily coated leaves and bin them — don't compost them
- 2.Thin plants or open up the trellis so air moves through; sweet peas climbing a solid fence are especially prone
- 3.Spray remaining foliage with a diluted baking soda solution (1 tablespoon per gallon of water) every 7-10 days to slow spread
Seedlings or young plants collapsing at the soil line, with stems that look pinched or water-soaked
Likely Causes
- Root rot from Pythium or Phytophthora spp. — almost always triggered by waterlogged, poorly drained soil
- Damping off in seedlings started indoors in soggy seed-starting mix
What to Do
- 1.Pull and discard affected plants; don't replant sweet peas in the same spot that season
- 2.Amend the bed with coarse compost or perlite before the next planting to improve drainage
- 3.If starting indoors, water only from the bottom and let the top of the mix dry slightly between waterings
Frequently Asked Questions
How long do Mammoth Choice Mix sweet peas last as cut flowers?▼
Is Mammoth Choice Mix a good sweet pea variety for beginners?▼
Can you grow Mammoth Choice Mix sweet peas in containers?▼
When should I plant Mammoth Choice Mix sweet peas?▼
Do Mammoth Choice Mix sweet peas attract pollinators and wildlife?▼
How much spacing do Mammoth Choice Mix sweet peas need?▼
Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
- BreederJohnny's Selected Seeds
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.