I am installing a hedge of 6' podocarpus columns along a fence spaced about 3' apart 9(measured from the center of each podocarpus column. I realize that the hedge will take about 2-3 years to fill in, but that is just fine. Now I need something at the base of the columns at a lower height.
I wanted to use lineal 3 foot clumps of 5 gallon agapantha's and combine them for interest with another group of plants in between the agapantha's. I was thinking of filling in a four foot lineal alternating space with a plant grouping of a 5 gallon asparagas fern in between a two 5 gallon deep burgany Lorpentalums.
I live in southern California about 2 miles from the beach. The soil is well amended and I can irregate about 2-3 times a week on a drip system (8-10 minutes).
I was wondering if anyone had other suggestions for the lower elevation planting area infront of the podcarpus columns?.. preferably not overly water consumption demanding.
Thanks for any input.

How wide/deep is the planting area? Are these going between, in front..?
My guess is when you start placing those 5 gallon things around, the space will fill more quickly than it sounds like what you think . (In other words, I don't think all that will fit, if I understand). The podocarpus at 3 feet apart still needs room for it's roots and branches to grow. You don't have a whole 3 feet between points to fill.

Mulch is a nice filler that conserves, not used, water.
Some annual flower or smaller scale perennials.

Just my 2 cents, as someone who's lived thru many overfilled planting schemes.

Thanks Sally, point well made....regarding overplanting.
Thank you very much.