Planning a Seaside Garden

Update on House Planning:

The builders are asking me to outline just where I would like the garden beds to go on our block. Already? I thought to myself.

Before the house has even started and before the final plans for the house are even drawn, I have to envisage and draw up a garden plan. Not the easiest request to fulfill.

But this is the process of construction that we follow. So I comply. Here is my rough sketch.

My scratching of the garden placement in front yard

We have saline soil, it is also a silty clay, and it is reactive, meaning it is prone to movement – the ‘triple bunger’ of worst soils. Fantastic! Not really.

Even sandy soils would have been easier to deal with, I think. But the soil tests don’t lie.

Salty Silty Clay

Garden Design

What kind of Garden do I want?

• One that is private, but not claustrophobic – some hedging plants
• Plants that require little weeding or maintenance
• Palms in pots?
• A retaining wall or raised garden to improve drainage as the soil will become easily water logged.
• A climbing plant espaliered along the fence?

Choosing Plants for Clay Soils

What plants would like to grow in poorly drained salty clay soil?

Beautiful lavender bushes at Amandine nursery

Lavender bushes will grow by the coast and will also tolerate salty soils, but need good drainage and thus a sandy soil. (which I don’t have). So they would have to grow in pots.

Perhaps I could grow some Bamboo in pots as a screening plant/informal hedge?

Apparently I could grow certain veges –

“..most productive plants require good drainage and soil that’s well cultivated to about 30cm depth for good root growth and development, beans and shallow-rooted vegetables such as loose-leaf lettuce can be grown in clay soil.

And then there is some ornamental species such as Day-lilies and Hydrangeas that like clay.

The BHG website describes Daylillies as Tough-as-nails. “It’s trumpet-shaped blooms each last only a day, but plants can bloom for several weeks because they produce many flower buds. Some varieties bloom several times through the summer.”

Nandinas are also very tolerant of clay soils and there are loads to choose from.

Winner Winner!

I was hoping to grow something easy to maintain – like this Nandina – tolerant of clay soils

As clay soils can tend to water log easily, care should be taken with garden design to allow for good drainage. Few plants are tolerant of water logged soils. If I lay down a good layer of loam on top, some ground covers might thrive as long as their roots do not become water logged. I can also improve the soil with compost and organic matter to aerate the clay, but it still is salty.

There are not that many garden plants that tolerate salty soil in high concentrations.

Here are some:

• Blanket Flower – sounds positively dreary
• Lantana.- No – it is a noxious weed
• Viburnum – maybe
• Yucca – Yuk! Enough said
• Cannas – I have an inexplicable aversion to these plants for some reason
• Prickly Pear Cactus – Seriously? – This is a pest that threatened to overtake farmland in the nineteenth century. Why would anyone want this in their yard? A definite NO.
• Lavender Cotton – previous info seems to exclude this range
• Seaside Goldenrod – another new plant I wasn’t sure about

Flowering native shrubs such as the Bottle-brushes, Melaleucas, might do okay in moderate clay whilst two Banksias: spinulosa and ericifolia are apparently very tolerant of clay. Even a Westringia might cope and they are a coastal plant. Sounding better.

I have successfully grown Banksias before from seed. You have to burn the cones to release the seeds

Lomandras and Dianellas are tolerant of all but the heaviest clay soils. Some sites recommend the ornamental grasses such as Pennisetem, for heavy clay soils, but as I am highly allergic to grass, perhaps I should forget about that species.

I think the iconic Australian native plants prefer free draining soils, and will struggle in clay soils without some soil improvement. Yareena™ Myoporum parvifolium is a native ground cover tolerant of a heavy clay. That might be useful. But sourcing this could be a problem.

The Native hibiscus might survive and Lilly Pillies are reliable for hedges or screens in clay soils.

“Clay soils can be very heavy and hard to dig, with a tendency towards water logging. While heavy clay soils will need significant improvement before most plants will happily grow.. Improved clay soils can hold nutrients well and therefore can be very beneficial to plants which like a lot of water and nutrient, including many large leaved or tropical plants.”

Kate Wall http://www.bestplants.com.au/about-us/a-guide-to-using-the-right-plants/choosing-plants-for-clay-soils

There seems to be hope that there will be plenty of plants that might grow successfully in my salty clay garden. Something I’ll Ponder About.

More things to research. Do you have any suggestions for me?