How to revive struggling Chinese Star Jasmine?

[DaveTorr]

So I’ve had some Chinese Star Jasmine in my backyard for approaching 3 years now. This was all planted at the same time and all purchased from the same Bunnings. The left side has flourished while the right side has continually struggled.

The sun travels towards the camera in this shot. In summer it goes almost directly straight overhead. In winter it’s angled to the left. This means the right side almost consistently gets sun for at least the first half of the day while the left side doesn’t get as much.

I’ve attached a screenshot of my feeding and pruning schedule. Liquid is Black Marvel and slow release is Osmocote All Purpose. Last year I also installed a soaker hose under the soil to try and give it access to more water incase the mulch was soaking it all up.

My only thought process is that because the right side cops much more sun I’m STILL not watering it as much as I should be?

Any suggestions on how to help it catch up to the left would be appreciated.

 

[MitchellMc]

Hi @DaveTorr,

Your rates of fertilising could be increased. Black Marvel is designed to be applied every other week or even weekly. However, as you've touched on, it's likely that the right-hand side is overexposed and is struggling due to this. Although it's referenced that Star Jasmine thrives in full sun, depending on your location, this might be too much for it. In my experience, my Star Jasmine receives around 4 hours of dappled sunlight in the afternoon and no direct sunlight, but it's thriving, covering a wall of my house.

It's a difficult situation as given the planting arrangement, it's not easy to adjust the amount of sunlight that side receives.

Your watering regime might have something to do with it. How often and for how long are you watering?

Let me tag @Noelle and @mich1972 to see if they have any thoughts.

Please let me know if you have any questions.

Mitchell

[Noelle]

Hi @DaveTorr 

In addition to the information Mitchell has requested, can you tell us what is behind the Star Jasmine on the left side of your image - the ones that are thriving? I can see the plants that are not doing as well have a paling fence behind them - what's behind the other row?

Full exposure to the sun may be partially responsible as may be your watering frequency but I'll wait for your response before making any further comments/suggestions.

[DaveTorr]

@MitchellMc During summer I’m trying to make sure they’re getting water at least once a week. If there is no rain, I’ll turn the soaker hose on for about 40-60 mins. Perhaps this is where they need to be getting water once every 2-3 days instead?

@Noelle the exact same fence paling is behind the ones on the right.

[MitchellMc]

I'd increase that to twice a week at least, @DaveTorr. Maybe even three times a week for 30 minutes each. 

Mitchell

[Noelle]

@DaveTorr 

Plants growing in full sun need watering more than once a week, especially over summer. Your current soaker hose program isn't sufficient for the fully exposed plants to thrive. Watering every 2-3 days except when it rains would be better practice for these plants.

I had previously had the thought the thriving row may have had better air circulation around them, which could account for their better growth, but if they are also backed by a paling fence, then that theory doesn't stand up.

Most likely more regular watering and feeding would be helpful.

[DaveTorr]

Thanks @MitchellMc and @Noelle for the advice. I’ll increase to every 2-3 days for watering (rain dependent) and see if that improves things.

Would there be much of a difference using the soaker hose or spraying directly onto the mulch with a garden sprayer?

[MitchellMc]

Provided that you run the soakers for at least 30 minutes, it should saturate the soil surrounding the roots @DaveTorr. If the surface soil is not adequately irrigated, you could switch to surface watering.

Mitchell

[DaveTorr]

I planted a bunch of Chinese Star Jasmine almost exactly 3 years ago. Over the years I’ve learnt about fertilising, pruning effectively, and even installing irrigation to more adequately water them. However one plant seems to have always struggled:

All jasmine plants in these photos were planted at the exact same time (April 9, 2022). In this first photo, this side of the fence is the side that cops the most sun. The plant on the left is the one that has continually been struggling all its life. I will say it’s currently looking quite nice and green, but it frequently has shown drooping and discoloured leaves in the past.

As a comparison, these are the same jasmine plants sitting directly opposite them on the more shaded side of the yard.

Keep in mind too, I heavily pruned this side of the fence 2-3 months ago as it was significantly thicker and bushier.

Basically my question is, do I keep persevering with the struggling jasmine or rip it out and start fresh? What prompted this thought is I recently planted some extra jasmine in another section of the garden last year and it’s well on track to overtaking this struggling plant. Should I start fresh and make sure it’s properly watered, fertilised, and pruned from the get go?

[MitchellMc]

Hi @DaveTorr,

It sounds like you haven't had any success with increasing your watering regime. Unless we’re able to determine why the Star Jasmine is struggling, pulling them out and planting more of the same is unlikely to fix the situation long-term.

It may simply be that the position on that right-hand side is too exposed, particularly to harsh sun and drying winds. If that’s the case, you might want to consider planting something that’s a little more tolerant of full sun and heat stress — perhaps Trachelospermum jasminoides ‘Tricolour’ for a tougher variant, or even an entirely different climber like Hardenbergia or Pandorea.

That said, if you’re still keen to persist, you could try giving the area a bit more protection — maybe with a temporary shade cloth over summer or by increasing organic mulch and watering duration just on that side.

Please let me know if you have any questions.

Mitchell