An Auckland family has seen a mysterious Mexican plant sprout metres in a matter of weeks.

Something is afoot in Auckland as tales of mysterious plants sprouting this summer come flooding in.

After Stuff revealed the Foy-Turner's potentially record-breaking Agave stricta plant, dozens of green-thumbed readers have sent in pictures of more sudden bloomers towering above them.

Perhaps the mightiest Mexican marvel was sent in from Eddie and Kath Lambert, measuring a whopping five metres.

But another monster has dwarfed them all, Kevan Humphries yet unknown Agave plant in Forrest Hill on Auckland's North Shore was measured at an unofficial 9m.

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The Agave stricta is native to Puebla and Oaxaca in Southern Mexico. It was first named and described by Joseph Franz Maria Anton Hubert Salm-Reifferscheid-Dyck in 1859.

Ines Schonberger​, a plant systematist and herbarium manager at Landcare Research in Lincoln, said all species of Agave are regarded as monocarpic – meaning they flower only once and then die.

"It takes usually many years before they flower and even if no viable seeds are produced, they will produce offsets to replace the plant that bloomed," she said.

"Some do not die immediately after flowering, it can take a while, but the growth point that produced the flower stalk will eventually die."

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However, there are a few species, in the more than 200 species of Agave genus, that are polycarpic and do not die after blooming.

"The clump forms with very narrow leaves such as in the stricta and might survive flowering."

Agave species require cross-pollination or another flowering plant to get pollen from, she said.

"The flowering age of Agave plants is determined on the overall health of the plant, the soil conditions and on the climate.

"Agave species like it warm. If they have some good growing years they can gather enough strength and nutrition to produce such a huge inflorescence.

"It's a very impressive plant indeed."