Everything in my Urban garden for Chelsea has cranked up a gear. It’s nonstop meetings, visits, e-mails and phone calls, and I’m thinking of camping at the depot in west London where the garden is being mocked up by Clifton Nurseries, which is the constructor.

The team travelled to Arundel, in West Sussex, for the third time to see how the structural sculpture that will dominate the garden is progressing. It’s designed to tackle the lack of privacy that affects so many city gardens. I also hope it will be a thing of beauty, creating a protective arm around the seating area, yet retaining enough transparency to prevent the space from feeling caged in.

We’ve had lots of teething problems, and my ideas have had to be tempered with a dose of what is possible in terms of engineering and budget. The result is striking and, I expect, something visitors will love or hate.

The 16ft x 16ft mocked-up garden is well under way, and teeming with life. Temporary wall panels are shunted back and forth, enclosing the heavy, stainless-steel tiered unit that will be clad in slate at Chelsea. Timber and metal templates represent the paving, bench and sculpture, enabling me to get a sense of scale and finalise positions. The idea is to iron out problems now, so it should all be more straightforward on site.

This has helped me realise that the garden is too busy. The worst areas are the awkward junctions at ground level between the sculpture, the water, the edge of the paving and the pockets of planting. The most difficult thing at this stage is to be flexible enough to make changes. I have decided the congestion could be eased by altering the shape of the pool of water and reducing the length of a sloping wall.

Only when a truckload of plants - some destined for Chelsea, others stunt doubles - arrives does the space begin to turn into a garden. I play with combinations, bemoaning the size of the planting areas. Bold structures, hundreds of plants - it dawns on me that I’ve designed a small garden with a big one trying to get out.

The challenge, over the next couple of weeks, will be to trim the excess while delivering the flower-filled oasis I’ve been envisaging since last summer.

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