Royal Amethyst Dahlia Bulbs

The reverse of the petal is a different color. That’s the whole trick here: each petal is deep violet on the face and pale lilac underneath, so a plant in a light breeze flickers between the two. In bud the flowers look almost black, which is unnerving for a week and then worth it.

What you get

• Graded tubers with a visible eye, packed in peat.
• Blooms 6–8 in across on plants 36–42 in tall — a large-flowered type that needs a stake in wind.
• Deep violet face, lilac reverse, with a small gold center that only shows when the flower is fully open.

Planting note

Large-flowered dahlias throw heavier heads than their stems expect. Put the stake in at planting, 2 in from the tuber, and tie in loose figure-eights as the plant grows. Doing it afterwards means driving a stake through the tuber cluster.

Planting

• Wait for warm soil. Plant two weeks after your last frost date, once the soil holds 60°F / 15°C at 4 in deep. Cold soil rots tubers before they wake.
• Set them 4–6 in deep, eye facing up, with 2–3 in of soil over the crown. Space 15–18 in apart so air moves between plants.
• Water once at planting, then hold off until shoots break the surface — a soaking wet tuber with no roots has nowhere to put the water.
• Full sun, 6+ hours. Stake at planting if you want straight stems; adding supports later breaks roots.

Season & hardiness

• Blooms 8–10 weeks after planting and keeps going until the first hard frost.
• Hardy in USDA zones 8–11. In zones 3–7 lift the tubers after frost blackens the foliage, or grow as an annual.
• Pinch the center shoot at about 12 in to double the stem count; more stems, smaller blooms.
• Deadhead spent flowers every few days. Left to seed, the plant stops producing new buds.