Writing about roses last week (The Land, May 16) reminded me of the value of plants with aromatic foliage as insect pest deterrents.
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Roses attract more of these than most plants but if, like me, you steer clear of chemical repellents, there is an answer.
It's called companion planting and means growing plants among your roses that caterpillars, aphids and mites, among quite a few others, prefer to avoid.
The brilliant thing here is that many of these aromatic plants are loved by friendly creatures like bees, hoverflies and ladybirds so it's an all-round win, win, what could be better?
I learnt the value of insect repelling plants when I noticed that bugs were totally ignoring three roses that I'd planted behind a clump of Artemisia Powis Castle: not a chewed bud, petal or leaf in sight.
Powis Castle (50 by 50 centimetres) has dissected, silvery leaves and is probably a cross between tree wormwood (A. arborescens, two metres) and common wormwood, A. absinthium (1.2 metres).
It smells more intensely than tree wormwood and is marginally more restrained.
Both are frost- and drought-hardy and unfussy about soil or aspect. Easy from cuttings.
Many ornamental sages (Salvia species) have aromatic leaves that repel leaf-eating and sap sucking insects, and flowers that attract pollinating bees.
S. nemorosa has upright purple flower spikes and there are many forms available of varying heights and flower colours.
David Glenn of Lambley Nursery kindly identified a form I've grown for several years as S.n. Ostfriesland.
Its dark purple flowers are carried well above its aromatic, dark green leaves and bloom for at least 2 months in early summer. I also have Caradonna and Amethyst - all three repeat flower if cut back after their initial flush.
Russian sage, Perovskia atriplicifolia, now Salvia yangii, is an excellent mid row plant with narrow, pointed grey leaves and branching spires of lavender flowers. Biennial S. sclarea Turkestanica is of similar size and form, but with attractively large basal leaves.
These are just a few from a huge genus (not all are hardy, need to check), with leaves that smell fairly horrible but luckily only when crushed.
Like Russian sage, rosemary (Rosmarinus officinalis) too is now classified as a salvia (S. rosmarinus) but will always be rosemary for remembrance to me. It has strong smelling, evergreen, needle-like leaves and pale blue flowers in winter. Easy from cuttings which will root in water on the kitchen bench.
Lavender (Lavandula sp.) is a perennially popular moth repellent, my cupboards are full of lavender bags, many of them old but still fragrant.
Lavender's blue, purple or white flowers complement roses perfectly, and by growing different species you can have bee-inviting blossom all summer. I have L. angustifolia Hidcote, with dark purple flowers, also a low growing white form Nana Alba, and tall, bushy, French lavender (L. dentata, 1.5 metres) with many months of pale mauve blooms.
Dropping to the front row, catnip (Nepeta cataria) has pale grey leaves with a sweet, faintly minty scent and tiny white flowers throughout summer. It is slow growing but easily increased by division. Many kitchen herbs including oregano, thyme and basil repel insect pests and are another front row option where they can be easily harvested.
Finally, French marigolds (Tagetes patula) attract bees and repel pesky soil nematodes and leaf chewing whiteflies.
Lambley Nursery (www.lambley.com.au) offer Artemisia Powis Castle and carry stock of several forms of Salvia nemorosa. Woodbridge Nursery www.woodbridgenursery.com.au offer S. nemorosa Amethyst.
