We'll be driving from Grand Canyon to San Diego and want to make sure we catch the big cactus. Do we have to get down to organ pipe monument or we'll see them along the way?

the big cactus?
Which one? Organ Pipe, Saguaro or Senita cacti?

We saw plenty of saguaro cacti driving the same route. An interesting footnote came from a gas station attendant, who advised us to look closely at the ones closest to the road for damage and holes. We saw this - reportedly from people shooting at them from the road.

We did not find the drive all that interesting, however - rather bleak and gray. The spring is the time to see the area in bloom, and we drove mid-summer when it was brutally hot. We are glad we made the trip, being from the eastern US and not having anything like this at home.

you will see plenty of saguaro cacti

What about the big organ pipe ones?

What do you mean by 'big cactus'? The classic image of a cactus is a saguaro and some of them get to be pretty big. You'll see them all over the place.

Organ pipe cactus - you'd have to drive down to Organ Pipe Cactus National Monument to see those. That's probably 2-3 hours out of your way.

Driving south on I-17 from Flagstaff to Phoenix, you will encounter your first giant sahuaro cactus when you descend to Black Canyon City from the (now closed) rest stop. As soon as the descent begins, you will see your first giant sahuaros, and they will continue to PHX where you pick up I-10 westbound on your way to SD. That variety of cactus is very sensitive to temperatures and altitudes. This cactus grows in a band dictated by the altitude. It is a very slow-growing plant, extending its first arms when it reaches 40 years old and older. It is a federally-protected plant. Most sahuaros bloom around early May, with flowers opening at their tips at night and pollinated by bats. Damage to or removal of this plant without government permission is a serious and punishable offense.

Gail, the holes you saw in the saguaro cacti may have been made by Gila woodpeckers! Check out this link:
http://www.desertmuseum.org/books/nh...rs.php?print=y

Those fist-size holes were indeed made by birds. They were seeking the moisture stored in the cacti. Other birds will use those holes to build their nests, raise their young, and be protected from marauding reptiles, hawks, and insects as well as the midday heat.

tanuki and USNR - now I feel really stupid - or maybe the gas station guy was really stupid. Anyway, I believed they were made by people shooting at them. Maybe they were shooting at the birds?

You would not be the first person taken in by people who like to pull the wool over others' eyes. Gas stations are not the best place to get accurate information about birds and plants, right?

Source of info is always important - why else would we all come to Fodors for medical, financial and life skills advice?

Do they have safaris to catch the big cactus? I'd think you'd need sturdy gloves and a really big net.

If you look at the saguaro cacti closest to the road, you will indeed find them peppered with bullet holes. Since the largest of these plants are over a hundred years old, they have seen a lot of gun toting yahoos from a wilder time.

During those times everyone carried a gun and target practice was commonly conducted on just about anything including these ancient 5,000 to 8,000 year old pictographs at the Great Gallery in Utah.

http://www.pbase.com/peterb/image/86046468

Thankfully these are now protected as part of Canyonlands National Park.

Looking at it another way, maybe you're looking at bullet holes in those cacti that were put there by
Wyatt Earp or John Wayne

Here's a link to Saguaro cactus facts. The one I find amazing is that a mature Saguaro with 5 or more arms would be estimated to be 200+ years old....plenty of time to collect small bullet holes and large bird nesting cavities.

http://www.desertusa.com/july96/du_saguaro.html