So far as I can tell the two species the petstore currently carries are
Giant Prickly Stick Insect (Extatosoma tiaratum)
Vietnamese Stick Insect (Ramulus artemis)
It is winter here so outside is not a viable source. I can't wait til spring! Then all my issues will be solved.
I am not sure where to acquire Privet here, I need to look into it more and see what I can find.
If you haven't already found the
KeepingInsects website, they cover phasmids and
what they eat. They also have caresheets for both
Giant Prickly Stick Insect (Extatosoma tiaratum) and
Vietnamese Stick Insect (Ramulus artemis) too.
Many English articles related to phasmids have been written by British authors where they are still common pets. They use terminology and native plant species that are common to them, but not elsewhere. What I find odd is most articles on the internet just copy the terminology and species, no matter their geographic location.
Anyway after much searching I can tell you that a
privet is shrub (found in the wild in Europe east to Asia) and is typically listed as a invasive species. Due to that it is not available in many places unless it is already spread to the area. If you do not know the name I doubt it is a problem in your area, and likely not available for you either.
Bramble is nothing more than a prickly shrub such as blackberries, raspberries, and roses. The more common plant term (botany)
is briar, and may help in your search along with the species themselves.
So I am looking to pick up a stick insect this week. I have done my reading and know the goto foods are oak leaves, rose leaves, berry bush leaves, and bramble leaves. However it is winter here in Iceland and some of those would be hard to find even in the summer here. I see that the pet store is feeding the sticks lettuce. Fears of pesticides aside is lettuce of any type a viable food source? Is there anything I can buy at the grocery store that would do the trick? Lettuce (romaine or otherwise), spinach, cabbage, live herbs of some kind? I also have some bean plants from my failed aphid experiments I could give them if that was an option as they are fast to grow and I can be sure nothing bad has been sprayed on them.
In the long run I plan to plant some raspberry bushes but that is going to take a while.
Romaine lettuce tends to be a emergency food source for keepers, as it is available year round. Few phasmid species can survive eating it, but even if a species can and will eat it some individuals can starve or develop health problems and die (not all individuals can adjust to it). If the pet store has been feeding them Romaine then those individuals though should be fine as they likely have already adjusted.
There is nothing else in grocery stores at least in the US that any phasmid would eat, including other types of lettuce as it does not work at all or does worse (including leafy greens such as carrot tops, kale, spinach, etc.). Sometimes I have read roses with stems from a flower shop/section of the store for food, but those are covered in various chemicals from growing and to prolong their cut life, and those tend to kill phasmids no matter how they are washed/cleaned. I mention the store bought roses just so you avoid them.
There are a few feeding options (
check the plant species on the phasmids caresheets first), but the obvious answer is to continue to feed them Romaine lettuce. Visit any local greenhouse, nursery, garden centers, and related to see if there is any plants that you can buy for them as well. You may be able to find a plant that is small enough and in a pot that you can keep indoors by a window to feed them from.
The other answer is to check wild plants in your area. I of course don't know your property, wooded areas, or such near you but look for evergreen plants that are still growing is a solution. If a plant is nearby cutting a few stems as needed (likely every few days) to feed your phasmids may be a option. You may find the perfect plant, and perhaps one not even listed as a food source, if you offer them what you find.
The last option is to check your country and local laws and see if having plants or at least their leaves shipped to you is a option. It seems in some places that is a option and a way for them to make money, that is shipping phasmid keepers leaves (I've read it several times on UK forums). In the same vein you may be able to have small plants or leaves shipped as well to you from greenhouse nurseries from nearby countries, check websites.
In the long run I plan to plant some raspberry bushes but that is going to take a while.
A good option, and one I would caution you to plant plenty of.
The native species I've had, Northern Walkingstick (Diapheromera fermorata) is 4" (10cm) maximum and the two you listed are 6" (15cm) so would eat even more. Mine could eat, stripping large leaves in a few days. A single one could eat about 1" (2.5cm) in about 15-20 minutes when it was eating. It ate much more than I thought it could, and was interesting to watch.
A good feeding tip in that aspect is to offer your pets less food more often, and will save your bushes. The leaves/stems even if kept in a container of water dry out rather quickly, and no need to waste your limited food source. Once the leaves begin to dry out it leads to dehydration and constipation in phasmids that eat them.
Another latter option some phasmid keepers do with varying success is to collect fresh leaves during the late spring/summer and freeze them until needed in the winter. Once a few leaves are allowed to thaw and clipped inside on a dowel rod "stem", most phasmids do well.
Best of luck.