How to Grow Sunflower Mammoth
Helianthus annuus 'Mammoth'
Your complete guide to growing Sunflower Mammoth.
📷 Wikimedia CommonsWhen to Plant Sunflower Mammoth
Planting windows vary by USDA hardiness zone. Look up yours by ZIP code.
| Zone | Start Indoors | Direct Sow | Harvest |
|---|---|---|---|
| Zone 1 | May – June | July – September | — |
| Zone 2 | April – May | June – August | — |
| Zone 3 | April – May | June – August | — |
| Zone 4 | March – April | June – July | — |
| Zone 5 | March – April | May – July | — |
| Zone 6 | March – April | May – July | — |
| Zone 7 | February – March | April – June | — |
| Zone 8 | February – March | April – June | — |
| Zone 9 | January – February | March – May | — |
| Zone 10 | January | February – April | — |
| Zone 11 | January | January – March | — |
| Zone 12 | January | January – March | — |
| Zone 13 | January | January – March | — |
Companion Plants for Sunflower Mammoth
✓ Good companions
Fix nitrogen in soil while using sunflower stalks for natural support
Similar growing requirements and compatible root systems without competition
Benefit from sunflower shade and wind protection while maximizing garden space
Benefits from partial shade provided by tall sunflowers during hot weather
Repel aphids, whiteflies, and nematodes while attracting beneficial insects
Act as trap crops for aphids and cucumber beetles, protecting sunflowers
Help break up soil around sunflower roots and deter certain pests
Attract pollinators and beneficial predatory insects while sharing similar care needs
✗ Keep away from
Produce juglone toxin that severely stunts or kills sunflower growth
Releases allelopathic compounds that inhibit sunflower germination and growth
May climb and overwhelm sunflower stalks, competing for light and nutrients
