Getting it to bloom

Why won't my Dahlia 'Mystery Day' bloom? (and how to make it flower)

Also called Mystery Day Dahlia (Dahlia 'Mystery Day').

More about dahlia 'mystery day'

About Dahlia 'Mystery Day'

Dahlia 'Mystery Day' · also called Mystery Day Dahlia · flowering

Dahlia 'Mystery Day' is a striking cactus or semi-cactus dahlia with spiky, twisted petals in deep purple-burgundy tones with lighter pinkish tips. Its dramatic blooms stand out in cutting gardens and borders. It flowers reliably from midsummer until first frost on sturdy upright stems. Toxic to dogs and cats per the ASPCA.

Plant type: flowering

The reasons dahlia 'mystery day' isn't blooming

Almost every non-blooming dahlia 'mystery day' traces back to one of these, roughly in order of how common they are:

Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.
Too much nitrogen feed, driving lush foliage at the expense of flowers (very common with general or lawn feeds).
The plant has not been deadheaded, so it stops flowering once it sets seed.
Irregular watering — drought or waterlogging at the budding stage makes buds abort.
It is still too young or was checked by a transplant and is rebuilding before flowering.

Feeding dahlia 'mystery day' a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.

The fix — how to get dahlia 'mystery day' to flower

Maximise sun. Give dahlia 'mystery day' the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers.
Switch the feed. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.
Deadhead regularly. Remove spent flowers often to keep it producing more rather than stopping to set seed.
Water consistently. Keep moisture even through budding and flowering — drought-then-flood swings make buds drop.

Light and feeding do most of the heavy lifting here. Dial in the spot with the light guide for dahlia 'mystery day' and get the feeding right with the dahlia 'mystery day' fertilising schedule — the wrong feed (too much nitrogen) is one of the most common silent reasons a healthy plant makes leaves instead of flowers.

Bloom season and what to expect

Dahlia 'Mystery Day' flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.

Post-bloom care so it flowers again

Deadhead, keep feeding lightly, and many will rebloom; collect seed from the best plants at the end of the season if you want to grow them again.

For everything else this plant needs day to day, see the full dahlia 'mystery day' care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.

Dahlia 'Mystery Day' blooming — frequently asked questions

Why won't my dahlia 'mystery day' flower?

Dahlia 'Mystery Day' blooms on the season's growth given enough sun, warmth and the right feed — there is no cold or photoperiod trick, just good growing conditions and a bloom-leaning feed. The most common reason it is not happening: Too little sun — most of these need full sun (or very bright light) to flower well; shade gives leaves, not blooms.

How do I make dahlia 'mystery day' bloom?

Give dahlia 'mystery day' the sunniest spot you have — for most bedding and fruiting plants, more direct light directly means more flowers. Move off high-nitrogen feeds and use a higher-potassium "bloom" or tomato-type feed as it comes into flower.

When does dahlia 'mystery day' normally bloom?