'Moonlight' Grevillea is quite fast, yes but prefers full sun. It's also as wide as it is tall, airy (see through) in growth habit, and your area there is quite narrow. You've already got two potentially big plants there in the Ceanothus. Are you planning to pull those?

How wide is that planting bed? You need something with an upright, narrow growth habit and low litter because there is a pool nearby...though it looks as though you have a tree and a queen palm hanging over the pool already...lots of litter from those?

Upright, narrow, tallish shrubs:

Grewia common name Lavender Star Flower

Syzygium (Eugenia) australe.

Some of the Pittosporum tenuifolium selections like 'Wrinkled Blue' or 'Tasman Ruffles' or 'Marjorie Channon'. Need regular, light tip clipping to achieve visual density.

Callistemon 'Slim'

Podocarpus, often recommended as a screening plant, but being in nature big trees they have big root systems that will bust masonry. Ditto for any Ficus, (and Ficus are even worse).

The new thing for boring old Ligustrum is for growers to sell it trained as an upright, relatively narrow shrub that can be kept trimmed pretty narrow and dense and yes it gets tall. It's not exciting but it is reliable. I've seen them for sale 8-10' tall which might give you almost instantaneous results.

Thanks Nil, awesome suggestions.

And for clarification on the Ligustrum do you mean Ligustrum japonicum?

Grewia grows quickly but can become a monster. It may also drop too much litter to be near a pool.

So funny, Thank you hoovb!!!!!

You and Nil13 give the best answers.. so clearly I confused you two.

Ligustrum japoniucum, yes indeedy.

hoovb we planted today based on your suggestion! Thanks again..

We used pretty big 25 gallon sized plants... we couldn't fit the fourth 25 gallon in, as there was too much equipment to plant in that area so we are going to have to fill in with a smaller one or just wait till the others fill in...