Looks like black aphids to me.
Insecticidal soap should do the trick.

-Robert

robert1971ÃÂ
thanks for your input, i am wondering if i have it here locally

I just googled aphids on gardenias and saw that insecticidal soap can damage gardenia's leaves. You might want to spray your plant with a jet of water to knock off as many aphids as possible. You can make your own insecticidal soap but I wouldn't leave it on your plant for long. Others with more knowledge about gardenias should be able to help.

Here is a link that might be useful: How to make your own insecticidal soap

Khourshed,
You want to use gentle dish washing liquid you can buy almost anywhere, it will say "all natural", just not the liquid dish washing liquids with bleach alternatives and such. Plain dish washing soap.
Mix a small amount of it in plain tap water.
Liberally spray all the leaves, and especially underneath of the leaves.
Wait at least 4-5 days before reapplying again.
You can literally wash that off also, in the sink and then after you get as much off as you can, then spray the plant.

robert1971, thanks for the tip, but i am afraid with high pressure water i will damage all my very soon blooming flowers - our flowering season started already in our partof the world

butterfly4u, dish washing liquid we have here is like jef, fairy. i will try to look for all natural ones i really doubt if i gonna find it

strange enough all my under leaf are clean, do you think if under leaf is clean will change the diagnosis !

Do you have access to Kneem Oil? OR any other type of horticultural oil?

If the spraying off method does not work with what is suggested, or if you can not find natural soaps, then I would use that.

By the way, if you don't do use a good jet of water, they will not leave and just hold on tight. You will loose the buds anyway if you don't:-(

No, aphids are notorious for hanging on anywhere they want. If anything, they will just spread.

When you say you sprayed it three times, with what?

Mike:-)

Mike,
i sprayed it with a liquid with very foul/bad horrible smell i took it from the nursery shop suppose to kill every thing and keep you plant in healthy. i bought it initially cause i had worms which eat my lemon tree leaf

If you are looking for a mild liquid dish soap, try IVORY
I have used it in the past & it does not bother the leaves