Facebook Questions and Answers for the 21st October 2011

Hello Facebook fans, thanks for your questions this week, here are Carly's replies:

Claire Aldrich

What's the best thing to under plant lilies with for an exotic look?

Hi Claire, the features of exotic gardens are often large-leaved plants such as ferns, palms and bananas. To achieve this look at ground level you could use ground-cover plants such as Bergenia (Elephant's ears), Sweet Woodruff (Galium odoratum), Heuchera and Hosta. Heuchera 'Yellowstone Falls' is a very good groundcover plant. Coleus are also good annual bedding plants which come in an exotic range of leaf colours, ideal for under planting. For flowers you could try short varieties of Nicotiana (Tobacco plant), Busy Lizzies and Nasturtiums for their exotic looking flowers and foliage. The exotic look is normally achieved by using hot and bright colours such as cerise pink, red, orange and yellow.

If your lilies are a tall variety you could grow them alongside red hot pokers, Chinese Lanterns, Tradescantia and Daylilies. I hope this gives you some ideas to start with Claire!

Colin Freeman

I have a spot in my border which is a pain i put plants in then they curl up and say bye bye any ideas?

Hi Colin, there could be quite a few reasons why your plants don't thrive in that particular place. New plants do have to be mollycoddled a bit after they've been planted, particularly when we get long dry spells as we had this spring. If your soil is sandy and prone to drying out it may just be that your plants didn't have enough water to establish their roots. New plants need constant watering in their first year to settle in well. Conversely it could also be that the soil was too wet and the plants rotted. Rotting happens in heavy clay soils and compacted soils which haven't been dug and cultivated for some time. Plants will find it difficult to grow roots in hard and compacted soil. The remedy in all situations is to incorporate lot of organic matter such as well-rotted manure and compost to help improve the soil. Digging will break up the soil and organic matter will aid drainage in clay soils and help retain water in dry, light soils.

Another reason for failure can also be planting too close to a large established tree or shrub. These mature plants have extensive root systems which not only congest the soil with roots but suck all available moisture out of the soil. It's also worth making sure the plants are suitable for the location - research the plant's hardiness, whether the plants need full sun or shade to thrive, and whether they might suffer in a heavy or light soil. The wind can play havoc with new plants, drying out and scorching foliage so offer them some protection if your site is windy. It's also worth checking you're not planting too deeply, smothering the stem of the plant and causing rotting. Plants should be planted at the same depth as they were in the nursery pot. Hopefully something here stands out as a reason why your plants won't grow. Best of luck Colin.

Valerie Dunne

Are tree lilys frost hardy?

Hi Valerie, tree lilies are fully hardy and will have no problems with our winter weather provided the soil is free-draining. If you're growing them in a container it's a good idea to move the container to a sheltered part of the garden for the winter or to bubble wrap the pot for insulation.

Aidan Vardy

Hi Carly. thank you for your past answers .This year I had some strawberries with black withered leaves ,some varities ok ,is this a disease and will it spread to other strawberries or can I spray next year , with what and when. With thanks.

Hi Aidan, there are a few diseases which may cause these symptoms. I would be able to make a more definite diagnosis with a photograph or further details about the affected plants. It could be powdery mildew which shows as a white powder on the upper leaf surface, or botrytis which is a grey, fluffy mould. If botrytis is the problem then you need to remove all dead leaves to improve ventilation around your plants. If you have powdery mildew then improving air circulation will help and you can also spray your plants with a fungicide. These are available at all good garden centres and will say on the bottle whether they are suitable for powdery mildew and when to apply. As with any chemical, do check it is suitable for use on edible crops first!

If the disease begins as irregular purple/brown spots on the leaves these are the symptoms of a fungal leaf spot. In this case remove any affected leaves and clear away dead material to help ventilate the plants. There are no sprays available to treat this problem. If the problem affects the older leaves, causing them to curl up and turn brown then your strawberries may have verticillium wilt. The youngest leaves remain green but the whole plant is stunted. If this is the problem you will need to completely remove the affected plants. Unfortunately there is no cure for this and as the fungus remains in the soil for many years it is best not to plant strawberries in the same place again. Alternatively you could try growing wilt-resistant varieties like 'Elegance'.

The only other possibility is Vine Weevil - the adults eat notches out of the leaf edges and the larvae feed on the roots, often killing the plant. They are a creamy white colour with brown heads. If you do spot any of these symptoms you'll need to use a nematode (parasitic worm) watered into the soil to kill the insects. These are most readily available online and are applied when temperatures are warm, from late spring. There are no approved chemicals for controlling vine weevils on edible crops.

Fungal conditions tend to thrive if plants are too close together as it provides warmth and humidity. Try spacing your future plants no less than 35cm apart and be vigilant about cleaning up dead material around your strawberries. Many fungal diseases over-winter on dead leaves. I hope this helps Aidan, best of luck.