a mediateam website

See a sample issue of The Irish Garden!

Ask Gerry

Flowers : Rock Garden Flowers

  1 - 6 of 33 answer(s)

Creeping Thyme as grass alternative

I tried to sow Creeping Thyme as grass alternative last August. I dug few inches off the existing clay soil, I added chicken manure and one layer of compost, 10-15cm of westland nutrient rich top soil, then seeds mixed with sand all around the garden but it wouldn't germinate (weeds are doing great though...!). I have a few questions now: What shall I do to stop weeds from spreading (I was thinking to throw granular weed killer once a month)? Anything you would advice to do, before I try again next spring? madster, Clongriffin, Co Dublin Posted: 10/10/2017

There is no true replacement for grass as a lawn plant. Thyme you could regard as a ground cover alternative.

Creeping thyme is native plant of sand dunes and some rocky places. The soil mix you created is far too rich.

The best advice would be to sow grass, as thyme will at best make a patchy cover with plenty of hand-weeding. It does not tolerate wear.

But if you want to try again, sow the thyme seeds and raise the plants in cell trays next spring and plant out in autumn. You will need about 15 or 20 plants per square metre.

Control weeds in the meantime by spraying Roundup, realising that this will kill all greenery.  



I have a bright green moss invading my flower beds, it doesn't seem to respond well to roundup, and picking is not very effective as there is too much to use as permanent workaround. Any ideas to kill permanently would be appreciated. laddy, , Co Cork Posted: 01/10/2016

Some people love a mossy effect.

Roundup does not affect moss. Use a path mosskiller such as Hygeia Mosgo.

  Plant identification

Plant identification

Can you please tell me what this flower is? It has returned again this year with no effort whatsoever. LOC2016, Dublin, Co Dublin Posted: 01/06/2016

It is lewisia ... a rock garden perennial.


moss treatment on sedum roof

We put sedum cuttings down on a roof 3 years ago, didn't realise we had to feed the sedum, waiting for the show of colour last year combined with a very dull summer, there is a lot of moss in place. We applied seaweed on it last autumn which I will do shortly again. Just wondering what type of fertiliser, could I use that won't harm the sedum but will reduce the moss, there is also a part were clover is growing. roof is north facing. found on nz website the ratio n12.6/ iron 8 and sulphur 1, can't find if sedum will thrive on this. Frederike, Castlebridge, Co Wexford Posted: 22/04/2016

SUlphate of iron might burn sedum, but the moss is not a big competitor. Seaweed is a tonic more than a food. Shake out some Osmocote granules or chicken manure pellets.
Remove the clover as it will take over.
North-facing is not ideal and tends to encourage moss as roof gardens do best in full light.
Small ferns might be a better bet, such as hart's tongue fern or polypody fern, and the moss wouldnt matter then.


Query for Autumn Planting

Have recently just fallen in love with gardening after never having done it before. I put in a large rockery (prob about 10M) and I have been busy planting away with summer flowers. My question is what are the best flowers to plant for autumn or seeds to sow. Have no idea what will last autumn into winter so any advice would be gratefully appreciated. CloG, Mullingar, Co Westmeath Posted: 09/07/2015

Most rock garden flowers flower in spring and early summer, with some in summer, and not much in autumn, but persicaria lasts well and autumn gentians and autumn cyclamen are brilliant.


Complete disaster

Two - level very overgrown garden. No topsoil or clay - only builder rubble, stones and sand.. Lower level sloping towards house with no retaining wall with wooden railing separating upper and lower levels. No access for mini digger. Two landscapers have said no to job with one saying it's the worst he's ever seen. Can you give me some advice please. We are senior citizens (68 & 69) but have removed most of the weeds by hand. Arwen, Rathdowney, Co Laois Posted: 30/04/2015

Weeds can be killed using Roundup, as a first step. 

With all that rubble, stone and sand, the drainage must be good, so why not turn adversity to advantage and have a dry garden. Some plants, such as lavender, cistus,  rosemary, russian sage, Convolvulus cneorum, abrieta, campanula and other rock garden plants, love dry conditions and they are easy to look after.

A dry garden can be surfaced with gravel, 5cm, and plants dotted in here and there, making a hole for them and using some soil mix to get them started. The dryness and the gravel keep weeds down. 

A dry garden can very attractive, unusual, cheap to establish and easy to keep. 



Garden.ie Members

Not a member yet?
Join now to:

Join Now

Existing Members

Forgotten password

Garden.ie CLUB

Join Ireland's first online garden club! Share pictures of your garden, make new friends and chat with other gardeners. It's simple to join and free! Register Here

Featured Members

Ask Gerry

Gerry DalyTry our unique advice service from editor Gerry Daly. Got a question right now? Search here to see if it has been answered already:

a mediateam website

©2017 Garden.ie. Mediateam Ltd, Media House, South County Business Park, Leopardstown, Dublin 18.

Tel (+353 1) 2947777 Email info@garden.ie

Website Design by KCO.ie