I've seen them on the flowers of kalanchoe, aloes, agaves, euphorbia, cereus species, gastoria & a few others. Primarily those with tubular shaped flowers, not so much on the cacti and their big open flowers.
Tally HO!

I don't have alot of spinny flowering cactus plants and I hadn't seen any hummingbirds on them or the desert rose over the past few seasons

I also have a few other hummingbird specific attraction plants and I hadn't seen them around as much as I thought they'd be attracted to them. I guess it's up to the hummingbird cause there are plants here that aren't even ment or colored for hummingbird attraction that still get some very odd hummingbird play time activity

Noto Lover,

If you want hummingbirds with your cacti, get lots of Cleistocactus and Arrojadoa - their flowers are constructed so that hummers can feast from them.

Otherwise, Aloes, Aloes and more Aloes are what I recommend, although hummingbirds will make crosses with anything in flower at the time (if you were trying to raise pure seed).

As members of the mega-toxic Apocynaceae family, it's likely that the flowers and nectar of Adeniums are poisonous, and hummingbirds would be wise to avoid them.

I've seen hummingbirds investigate cactus flowers, but bees, ants, and other insects are their intended pollinators. In my garden there are lots of easier food sources, like Aloes and Echeveria nectar, and the hummers leave cactus pollen to the bees:

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Brad

>>> As members of the mega-toxic Apocynaceae family, it's likely that the flowers and nectar of Adeniums are poisonous, and hummingbirds would be wise to avoid them.

Brad, forgive me for saying so, but that doesn't really make sense!

If the flowers and nectar of Adeniums were poisonous, that would kill any pollinators, and without pollinators, Adeniums would have died off long ago.

I suspect that even if the rest of plants are toxic, their flowers aren't :)

-R

There's been a lot of research on "Toxic Nectar" - it appears to potentially have evolved to resist or at least discourage nectar robbers without negatively affecting pollinators "too much".

Basically, Toxic Nectar has alkaloids in it that can prove poisonous in some cases to certain insects or other nectar "antagonists" (the pollinators being the "protagonists" in this line of thought).

It's a fascinating field of research.

Cheers,
Tristan

Very informative posts-Thanks Everyone!

I didn't think about desert rose being toxic. But I know the bees and butterflys are all over the butterfly weed flowers, though few insects can tolerate the sap of the stem and leaves. I think the red milkweed beetles are really cute, but destructive. There are plenty of wild milkweeds growing, but they have to find the ones in my garden :-(

from what I have read about Adenium species, they are pollinated by insects (bees, usually), not hummingbirds.

If the flowers and nectar of Adeniums were poisonous, that would kill any pollinators, and without pollinators, Adeniums would have died off long ago.
~R

Interesting. That does seem logical. However, the problem here is what I meant by the term 'poisonous', and to whom. My assumptions are different from yours.

All parts of the oleander, including nectar, are toxic to mammals. The tissues and fluids contain cardiac glycosides, very potent toxins that make hearts beat erratically, and effect the central nervous system. Additionally, the Wikipedia article linked below makes this comment: Many of the Oleander relatives, such as the Desert Rose (Adenium obesum) found in East Africa, have similar leaves and flowers and are equally toxic.

So, I assumed, perhaps incorrectly, that hummingbirds (with hearts) would also be sensitive to Adenium toxins, and other pollinators, like bees and other insects, would not be poisoned. That may or may not be correct, but insects don't have hearts and blood like ours, and birds do. Obviously poisonous Apocynaceae have to get pollinated, but my guess is that, like many cacti, the natural pollinators of adeniums do not include birds. Interesting question R. ;)

Thanks Tristan! The evolutionary biology of toxins is fascinating. There is an ongoing battle in the mountains near me between salamanders who make an extremely potent nervous system toxin in their skin, and populations of their predator, garter snakes, who are gradually adapting to the amphibians increasing content of tetradotoxin. Apparently there has been a see-saw between the numbers of salamanders and garter snakes that has been going on for decades (or longer). It is evolution happening in the easily observable time frame of just a few years. :)

Brad

Wikipedia on oleander

My hummers love the Echeverias and Aloes. The winter blooming Aloes are especially good as they feed the hummers when there is less other types of nectar available.

If the flowers and nectar of Adeniums were poisonous, that would kill any pollinators, and without pollinators, Adeniums would have died off long ago.
~R
Interesting. That does seem logical. However, the problem here is what I meant by the term 'poisonous', and to whom. My assumptions are different from yours.

All parts of the oleander, including nectar, are toxic to mammals. The tissues and fluids contain cardiac glycosides, very potent toxins that make hearts beat erratically, and effect the central nervous system. Additionally, the Wikipedia article linked below makes this comment: Many of the Oleander relatives, such as the Desert Rose (Adenium obesum) found in East Africa, have similar leaves and flowers and are equally toxic.

So, I assumed, perhaps incorrectly, that hummingbirds (with hearts) would also be sensitive to Adenium toxins, and other pollinators, like bees and other insects, would not be poisoned. That may or may not be correct, but insects don't have hearts and blood like ours, and birds do. Obviously poisonous Apocynaceae have to get pollinated, but my guess is that, like many cacti, the natural pollinators of adeniums do not include birds. Interesting question R. ;)

Brad

Interesting topic.

First, however, I would caution anyone from relying on Wikipedia as a resource. There are times that it is accurate but on a number of occasions I have found it to contain grossly erroneous content. (The result of having no screening process for those contributing the information -- literally anyone can post what they believe to be the facts.)

Next, Brad is correct, land3499, in that when discussing what is poisonous, one must consider to what degree a substance is poisonous and to whom/what. Just because a substance is poisonous, that does not mean it will cause any great harm. For example, the poison in question might cause the consumer to feel a bit queasy or give them an upset stomach or cause them to vomit -- none of which are life threatening consequences. In such cases the poison simply acts as a deterant.

Then there is the matter of to what organism that substance is poisonous to. For example, chocolate is poisonous to dogs. Will it kill one? Possible but not likely. Will it make them sick/vomit? Very often. Yet chocolate is obviously not poisonous to us. This is not an unusual situation. There are any number of substances which are poisonous to us but not to other mammals or other organisms and vice versa. Just one more example --woody nightshade. All parts of woody nightshade are poisonous to humans. It is unlikely to kill you but rather will give you an upset stomach. However, birds commonly eat the berries without any ill effect. This whole issue is why it is so hard to find a reliable listing of "dangerous" plants to have in one's house or yard. Such lists do not go into degrees of toxicity nor species specific sensitivity to the toxin. Instead they often erroneously assume that what is toxic to one organism is toxic to all and assume that poisonous must equal deadly.

Getting back to the nectar question, again it would be interesting to research this topic. It would make sense that a plant might use low levels of a toxin to discourage organisms which will not prove to be good pollinators from visiting their flowers. Afterall, sex isn't cheap (get your minds out of the gutter folks :D ). Production of nectar, pollen, even of just the flowers is an energy costly expense for a plant. It would not be in the best interests of the plant to supply food for organisms that will not pay it back by pollinating its flowers.