Getting it to bloom
Why won't my Giant Arrowhead bloom? (and how to make it flower)
Also called Giant Arrowhead, Aztec Arrowhead, California Arrowhead, Giant Duck Potato (Sagittaria montevidensis).
More about giant arrowhead
About Giant Arrowhead
Sagittaria montevidensis · also called Giant Arrowhead, Aztec Arrowhead · flowering
Sagittaria montevidensis is a robust emergent aquatic perennial native to South America (Uruguay, Argentina, southern Brazil) and naturalised in parts of the southern United States and California. It produces very large, arrow-shaped leaves and impressive white three-petalled flowers with dark maroon basal spots on tall racemes throughout summer and into autumn. As the tallest and most dramatic Sagittaria species in cultivation, its most important care requirement is adequate depth — plant in water 10–15 cm (4–6 in) deep with full sun for maximum size and flower production. Sagittaria species are considered non-toxic to cats and dogs.
Plant type: flowering
Watch for — Invasive spread by seed: Sets large quantities of seed that can germinate prolifically in warm climates; deadhead spent flower stalks before seed dispersal to prevent unwanted spread, especially near natural waterways.
The reasons giant arrowhead isn't blooming
Almost every non-blooming giant arrowhead 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 giant arrowhead 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 giant arrowhead to flower
- Maximise sun. Give giant arrowhead 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 giant arrowhead and get the feeding right with the giant arrowhead 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
Giant Arrowhead 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 giant arrowhead care brief and its watering schedule — a stressed, badly watered plant rarely has the energy to flower at all.
Giant Arrowhead blooming — frequently asked questions
Why won't my giant arrowhead flower?
Giant Arrowhead 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 giant arrowhead bloom?
Give giant arrowhead 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 giant arrowhead normally bloom?
Giant Arrowhead flowers across its growing season (mostly summer) and, kept fed and deadheaded, can bloom for many weeks or right up to frost.
What should I do with giant arrowhead after it flowers?
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.
What is the single biggest mistake stopping giant arrowhead flowering?
Feeding giant arrowhead a high-nitrogen general feed and growing it in too little sun — you get a big leafy plant and almost no flowers.
Keep reading
- Giant Arrowhead care — the full brief (light, water, humidity, problems, pet safety)
- Giant Arrowhead light needs — usually the first thing to fix for flowers
- Giant Arrowhead fertilising — the right feed for buds, not just leaves
- Should I water my plant? The simple check
- Why is my plant wilting? Wet vs dry
- Underwatered plant — signs and rehydration
- Why won't my peace lily bloom?
- Why won't my jade plant bloom?
- Why won't my tomato bloom?
- All 4114 bloom guides in the Growli library