Top Questions About Mexican Sunflower Plants

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Questions About Mexican Sunflower Plants

Asked by
Willia1 on
August 28, 2012

Q. Mexican Sunflowers/Tithonia

My Mexican Sunflowers are about 6-7 feet tall but there are no flowers on them yet. Should I pinch back some of the green sprouts on the sides? Or do I need to just wait? I live in CT.

Robin

Answered by
Nikki on
August 29, 2012
Certified Expert
A.

I would add a phosphorus rich fertilizer, like bone meal, to the soil. Plants frequently fail to bloom due to low phosphorus. This article has more information: https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/phosphorus-plant-growth.htm

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Asked by
joycelenhardt on
September 25, 2012

Q. Mexican Sunflower – Dying Leaves

We have several giant Mexican sunflowers. Leaves are constantly dying, which makes the bushes much less attractive. Do they need to be sprayed with something to counteract this? Thank you!

Answered by
Heather on
October 10, 2012
Certified Expert
A.

It may have a fungus. This could cause the leaves to brown and die. You can spray the shrub with a fungicide to treat this possibility.

It may also be getting too much water. It is a plant that likes it drier than wetter. If the soil is not drying out enough between watering, this can also cause brown leaves.

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Asked by
Mariano on
July 17, 2014

Q. mexican sunflower leaves sometimes look stressed at night

The leaves look stressed and down when I see them in the morning but later in the day they are nice and green. Is this normal?

Answered by
theficuswrangler on
July 18, 2014
A.

It probably has to do with moisture and the way the plants handle dry environment, shutting down their processes during the hottest part of the day and the night -- that's when they look wilted -- then opening stomata, and moving moisture stored in their roots during the night into the plant tissues when the sun is shining.

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Asked by
Terri teeter on
November 26, 2015
20141

Q. Mexican sunflower

If I collect the seed from this year’s plants and plant them in the spring, will they remain true and produce?

Answered by
Downtoearthdigs on
November 28, 2015
Certified Expert
A.

There are several varieties of Mexican Sunflower and some are hybrids.
If your plant is a hybrid the seeds may differ from the parent plant.

https://www.gardeningknowhow.com/ornamental/flowers/mexican-sunflower/planting-mexican-sunflowers.htm

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Asked by
edjamieson on
October 18, 2017
52722

Q. Mexican Sunflowers

I\’m a first time grower of sunflowers. What should I do in the fall? Will the plants come back next year?

Answered by
BushDoctor on
October 18, 2017
Certified Expert
A.

You should definitely harvest the flowers right after they die. They will usually be eaten by animals and won't have a chance to re-grow. Collect these and replant next year.

Here is an article for more information: https://www.gardeningknowhow.com/ornamental/flowers/mexican-sunflower/planting-mexican-sunflowers.htm

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Asked by
Cathy Vakil on
November 7, 2017
Kingston, Ontario, Canada

Q. Tithonia seed collection

I have tithonia plants that just started flowering a few weeks ago (today is Nov. 6) and I have a number of flowers now but none have dried out to remove seeds yet. We had our first frost last night and there will be frost most nights from now on. Should I wait until the flowers dry out more on the plant and cut them off to keep the seed for next year, despite the frost, or should I cut the flowers off now and let them dry out inside? Or should I cut the flowers off and put them in water inside until the flowers dry up?

Answered by
BushDoctor on
November 7, 2017
Certified Expert
A.

They won't continue to mature off of the stem, but I would say that your best bet is to harvest them now, and let them dry. You may get some seeds, or you may not. I fear the frost will destroy them, so it may be best to go ahead and try to salvage some.

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Asked by
per6247 on
December 5, 2017
Homosassa fl. 34446

Q. What is the name for the mexican sunflower that gets about 20 feet tall.

Do I cut the stems of a 20 foot tall mexican sunflower or just take off the dried flower? I have cut the stems to about 2 to 3 feet in the past but the plant is not bushy; is this the wrong thing to do???

Answered by
BushDoctor on
December 5, 2017
Certified Expert
A.

They can handle a good pruning, so this will cause no harm. Regular deadheading will keep it healthy. You can cut the vine by about half, and it will not affect negatively in any way.

This article will give you more information about the plant (even though it is for the shorter cultivars the care will be the same): https://www.gardeningknowhow.com/ornamental/flowers/mexican-sunflower/planting-mexican-sunflowers.htm

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