The Life Cycle of the Saguaro Cactus

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Saguaro Flower Buds (NPS photo)
Saguaro buds begin to appear in mid-April around the top of the main trunk and arms.

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Saguaro Flowers (Photo by Hal Coss)
The buds open into large white flowers from late April through early June. Each flower opens in the middle of the night, and closes the following day. Saguaro flowers are pollinated by nectar feeding bats, birds and insects.

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Maturing Saguaro Fruits
After a saguaro flower has been pollinated, it begins its transformation into a fruit. Complete ripening takes approximately 30 to 40 days. Dried flowers often remain attached to the ripening fruit.

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Ripe Saguaro Fruits (Photo by George Olin)
Near the end of the ripening period, the bright red fruits begin to split open. Inside are approximately 2000 tiny black seeds. Both the flesh and seeds are consumed by a variety of desert animals.

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Saguaro Seedling
If a saguaro seed falls in the right place, and at the right time, it may germinate and begin its long life. Only a few of the seeds a saguaro produces in its lifetime will germinate and grow to maturity.

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Young Saguaros Under Nurse Tree
For the best chance of survival, saguaro seedlings need the protective cover of a "nurse plant". The shade and additional moisture under the nurse plant is crucial to the survival of young saguaros.

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Arm Growth
In Saguaro National Park, saguaros begin to grow arms at about 65 to 75 years of age. Since the flowers grow at the ends of the main trunk and arms, additional arms allow the saguaro to produce extra flowers.

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Mature Saguaro
A mature saguaro is considered to be at least 125 years of age. Average life spans are usually 150 to 175 years of age, but may be longer in some individuals.

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Cristate Saguaro (Photo by Larry Cannataro)
While most saguaro cacti grow in a typical fashion, a few individuals will grow in an atypical form known as a cristate or crested saguaro. These bizarre looking forms often grow as a crest, but may also take other shapes such as balls or simply grotesque blobs.

Last updated: September 10, 2003