Did you buy the plants at the same time? There are different varieties of star jasmine, and one may have larger blooms or be more cold hardy than another.

Is one in a pot and the other planted in the ground? A plant in the ground is usually better off than one in a pot. Its roots are better protected from winter cold, and most soil is moderately fertile. Potting soil has almost no nutrient value; its primary attribute is the fact that it is sterile medium—no disease organisms. You have to add fertilizer, and not just NPK, but the micro nutrients necessary for healthy growth. You did say you may have used more fertilizer on the plant with the larger blooms. This is the most likely reason.

If they are both in pots did you use the exact same potting soil when transplanting them? I have seen major differences in different bags of the same brand of potting soil. Even expensive brands have disappointed one bag to the next.

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hi mindshift thank you for the reply. Yes both plants were purchased the same time and both reasonably mature the same variety. I live in sydney so a reasonably warm temperate climate it rarely gets cold and certainly never snows so i don't think it can be temperature. Yes the one with lesser blooms despite getting more sun is in a large pot as you can see in the picture. It is also the lesser fertilized one. It has a creeper plant in the pot with it. The one with better blooms gets less sun, but it has more fertilizer and is in its own soil rather than a pot. Both plants were planted with potting mix soil.

anyone else have any ideas or is mindshift the only person willing to help me?

Does anyone think drainage can play a factor in the poor bloom? i.e. im concerned maybe water is pooling at the bottom of the large pot and its not draining properly

Can you post close ups of each plant to ascertain if they are the same species or cultivar?

why is no one responding or helping me?

Well, speaking for myself I am the other side of the world in a different time zone and have a life.

I can’t think of any reason other than either you have two different cultivars or it’s all the variables you yourself have identified. Fertiliser, exposure, size of root run and light.

People are very helpful here. If they don’t answer they probably don’t have anything useful to offer. Also most forum members are in the northern hemisphere and are in winter, so perhaps not thinking much about gardening.

Both plants look lovely to me.

Sorry, I mostly only look at the orchid forum.......I have a variety of Star Jasmine and my Next Door Neighbour has a different variety. Same aspect, facing NE.

Her variety is on a more compact plant, the blooms are a "better" shape and there are more of them.

Pretty tough plant, so I do not think culture would make much difference, though some sunlight seems essential.

That stuff next to my name is the US Cold Hardiness Zone which comes in handy if you ask questions on forums.

The one in the second close-up shot also has broader petals relative to their length so might in fact be a different form of star jasmine than the other. Different to the extent of being a different named clonal cultivar or merely at the level of being (originally) a different unnamed seedling (one that started with the sprouting of a seed somewhere, even though production facilities have probably been using cuttings since).

If you clip some samples of each and compare them with star jasmines at nearby nurseries you may find one of them at least is in fact an example of a named cultivar. And that a genetic difference is why it behaves differently from the other one.

Otherwise the smaller flowers - and paler leaves - of the one are presumably due to it being stuck in a pot, as discussed previously.