Q&A with garden designer Dawn Isaac

DawnIsaacDawn Isaac is an accomplished garden designer and mother of three, and specialises in garden consultancy, planting design and contract management. She joined us in May 2012 to answer questions ranging from garden design to planting techniques.

With a Chelsea Flower Show medal under her belt, and the New Talent Award, she also writes for the Guardian on design issues and is a gardening consultant on CBeebies show, Mr Bloom's Nursery.

Flower gardening | Garden design | Seasonal plants | General questions


Flower gardening

Q. Queenofsiburbia: We live in a very exposed rented cottage in flat, arable land in drought-blighted Hertfordshire, in the grounds of a deserted farm. Our garden consists of lawn, a Leylandii hedge hacked down to shoulder level and a few large conifers etc (as well as weeds and lots of snails, which I am working on).

Having found out that lavender was a traditional crop in this area, I have decided to plant all borders with loads of it but I wonder if you can suggest any other plants that might do well, particularly fast-growing voracious floral climbers, which aren't expensive. We have three hacked-up Leylandii trees providing protection from the prevailing wind and I would love them to go but cannot think of anything which could replace them quickly enough as we'll only be here for maximum of two years.

A. Dawn Isaac: That hedge is going to prove tricky if your beds are anywhere near it. Not only will they cast a lot of shade in some areas but their roots will mean that your soil is probably very dry and impoverished.

Before trying to plant anything I'd get a lot of organic matter into the ground. I tend to order spent mushroom compost by the cubic metre for my garden. It works out much cheaper than buying small bags and you can use it not only to dig into the soil, but also to lie as mulch on top of the beds. If you do this after you've had lots of rain, or after you've given the plants a good soaking, it will trap in the moisture and cut down on the weeding too - what's not to love!

In terms of fast-growing climbers, I'd suggest a rambling rose. They will put on a couple of metres in a season without pausing for breath. However, voracious climbers need something substantial to climb up. In my own garden I have one heading up a tree (you can train them to do this by attaching a strong rope between the tree and the point where the rose is planted).

However, if you are only there for a couple of seasons I would be tempted to invest in some climbers that will reach their potential in a single season. Later-flowering clematis are ideal. I particularly love Clematis Etoile violette but there are loads to choose from (see my answer to Dietstartmoz below for planting advice). You could grow them up a structure in your borders or even in large pots. Also, why not try some annual climbers such as sweet peas?

And yes, if they get enough sun, lavenders should do well. Again, for low cost and quick results, you could also invest in some packets of hardy annual plants - things like love in a mist, poppies etc would give you fantastic summer colour and you don't get much more anti-suburbia than these kind of plants.


Q. Discrete: I'd love some help with one of my flower beds. It is an island raised bed, approximately 3m x 2m and 50cm high. In the centre it has a rose 'Buff beauty' which is doing well and expanding to fill most of the bed. Around it, when the rose was still small, I planted some of the plants that I could get from cuttings from my garden: rosemary, thyme, sage, pinks, sedum spectablile and madonna lilies.

Unfortunately, now that the rose is large and in full bloom for a long season, all those plants clash horribly with the colour of the rose (apart from the madonna lilies, which look lovely growing through it). Can you suggest some plants which are likely to like the same conditions but which have flowers in colours which will look better with the rose?

A. Dawn Isaac: I have to admit, I would always hesitate planting anything on the apricot/yellow palette for just this reason - it's really hard to find anything which goes with it. If you want to embrace the idea of contrasting colours then blues, or perhaps, purple/blues would provide a good companion, but I'm guessing from your reaction to things such as rosemary and sage, this isn't appealing to you. Of course, it may be that it's the pink shade of the sedum etc which is distracting. I would suggest removing these and seeing how you feel about the other plants. You could add to this range with species such as Veronica spicata, lavender and Nepeta (catmint).

Another option is to highlight the rose itself as the centrepiece and make a real statement. How about a sea of Stipa tenuissima, giving you a moving mass of grass underneath the rose? It would be happy in a similar spot to the other plants you mention, so should work really well. If you also increase the number of Madonna lilies you will create quite a 'wow factor' in this bed.

Q. Funnyperson: Do you have a particular theme in your gardens? I have a north-facing dry shady patch in the garden where I have this year planted some astrantia, hosta, acanthus and a tree lily, which will grow up into the sun. I would like to know what other plants you think might be good companions? Also what would you grow under a rampant ivory climbing rose?

A. Dawn Isaac: No, I'm quite adaptable in garden style, but my own is very much a romantic family garden.

Dry and shady is always a tricky combination. To be honest, you may even struggle with the plants you've already put in, unless you add a fair amount of organic matter (well-rotted horse manure, spent mushroom compost etc).

"One of may favourite plants to lighten up a kind of dull site is a Lamium maculatum - the cultivated version of the common deadnettle. It spreads well and if you choose something like 'Beacon silver' the pale leaves really glow in the shade. Also, the purple flowers are a great source of nectar for bees." 

One of my favourite plants to lighten up this kind of dull site is a Lamium maculatum - the cultivated version of the common deadnettle. It spreads well and if you choose something like 'Beacon silver' the pale leaves really glow in the shade. Also, the purple flowers are a great source of nectar for bees.

You could also try a few other dry shade stalwarts: Liriope muscari, Brunnera macrophylla, Vinca minor, Dryopteris filix-mas and Euphorbia amygdaloides var. Robbiae. All could become invasive in more welcoming soils, but in dry shade they will be beautifully well-behaved.

Garden design

Q. TheHouseOnTheCorner: I am a newcomer to gardening. My children love their trampoline but I hate the way the lawn beneath has turned to nothing but a mud patch, so I recently planted hostas underneath it as I was told they like shade. They seem fine so far and it looks quite interesting. Will they grow large there and what other shade-loving plants might like the area? I have clay soil.

A. Dawn Isaac: There are loads of plants which like shade, but if you plant them under the trampoline you'll want something that won't get too high. Why not try Viola purpurescens, a lovely, spreading plant with a pretty blue flower in spring. Or perhaps such plants as astrantia, lamium odorata and pulmonaria. Also, there are a couple of germanium species which take shade (I'm talking the cottage garden geraniums, not the pelargoniums here!) geranium pheum and geranium odoratum.

"I would suggest you sink the entire trampoline into the ground. It might sound radical, but you will find it much less dominating in the garden, plus a lot safer for the kids."

However, I would suggest you ditch the lot, dig up the hosta, and sink the entire trampoline into the ground. It might sound radical, but you will find it much less dominating in the garden, plus a lot safer for the kids as there's not the extra height form from which to fall. I've got some instructions about sinking trampolines here.

Q. SwallowedAfly: I have a huge garden with fencing issues that I can't afford to resolve at the minute. I have a gap in my garden of about 5-6m, which is bare. What can I plant there that would grow density and height quickly? I was offered some established laurel but I'm really not keen on those kind of waxy leaves. Something green, low maintenance and with flower at some point of the year would be ideal.

A. Dawn Isaac: For a quick-growing shrub or tree, I'm a big fan of Sabucus nigra 'Black Lace'. It's an elderflower - but with big bonuses. Not only has it got gorgeous black, delicately-cut leaves and beautiful pink flowerheads in May, but it will grow like crazy getting to a good eight foot high and you can also use it to make elderflower champagne.

If you don't like the dark leaves, there are golden-leaved varieties, too, such as plumosa aurea. If this isn't your cup of tea, you could also try viburnum opulus 'sterile', a buddleja or a forsythia, but I think the sambucus would be a far more unusual and interesting choice.

DawnIsaacHopscotchQ. Dietstartsmoz: We have a typical low maintenance garden-patio, decking, small lawn surrounded by pebbles and a couple of flower beds in a brick wall-and very few perennial plants.

I would like to plant some things in the pebbles to 'soften' the garden but don't know what to use. I have put a couple of things in- a clematis to grow up the shed etc but they have all died. Not enough water? I don't mind what - grasses, flowers, I just don't know where to start. Can you help?

A. Dawn Isaac: The real trick is to make sure the soil beneath the pebbles is really good. If you add enough organic matter (yes, I've mentioned it before, but it's the key to everything) - things like rotted down garden compost - it will improve the soil and help it keep hold of water. You can then plant into it and put the pebbles around it again, a bit like a mulch.

Then, it will depend on the aspect; sunny/shady/north/east/west facing. Without more information it's difficult to advise, but personally, I always like Alchemilla mollis; it's an easy, low-growing plant, good leaves, and a frothy acid green mini-flowers. If you need a climber, a clematis should work but a couple of pieces of advice: first, plant it a couple of inches lower than it was in the pot. Second, water it very well before it goes in, water the planting hole too, but let the water drain away and give it a good soaking once a week until it's really got going. Other than that, it will like the pebbles. They help keep its roots dry. If you have a big shed, try Clematis montana. Beautiful, pale pink spring flowers.

Seasonal plants 

Q. Inmysparetime: I work in a day nursery and want to make a willow tunnel to add height and interest to a dull grass patch. What is the best time of year to buy withies, how much (ballpark) would be enough for a 2m x 1.5m high tunnel cost?

I can weave it and maintain it once it's in, but gardeners will trim grass nearby. How much buffer do I need between the tunnel and the grass to prevent gardeners killing the willow?

A. Dawn Isaac: You can buy withies from November to February when the plants are dormant. It's relatively cheap - £40-50 for a 2m run (many places sell kits mail order) and I'd leave at least half a metre as a buffer.

Q. Marshmallowpies: I'd love some advice on planting for foliage/winter interest. I am very much a spring flower lover, so my garden looks great about now but pretty dull in winter. I have planted a few shrubby plants so it isn't all just flowers, like fuschia and hydrangea, but even these die back in winter so there is nothing to look at. I need some advice for foliage that will look good all year round. Have avoided hostas as I hear slugs love them.

"I'm a big fan of heucheras; they have a brilliant purple foliage and evergreen. Plus they're easy to grow in sun or partial shade and really take almost no effort. My personal favourite is Heuchera 'Obisdian' which is incredibly dark but there are a huge number of varieties to check out."

A. Dawn Isaac: I'm a big fan of heucheras; they have a brilliant purple foliage and evergreen. Plus, they're easy to grow in sun or partial shade and really take almost no effort. My personal favourite is Heuchera 'Obisdian', which is incredibly dark but there are a huge number of varieties to choose from. You could also add some topiary - I have mostly herbaceous perennials in my beds, which die down in winter but I also add clipped box balls which give structure in the barest months. Also, if you have a shady area you could add some hellebores, which will not only give you some winter foliage but also flowers.

Q. Sarimillie: I have four large trees growing on some raised ground right at the bottom of my garden. The snowdrops and bluebells were gorgeous, but all gone now. What can I plant under them that will look nice the rest of the year, and cope with shade? I'm thinking ferns, vinca, epimediums and maybe bamboo, and it would be great to have the names of some specific varieties you've found to be effective in these conditions. And if you have any tips for including some colour, that would be amazing.

A. Dawn Isaac: One of my favourite plants to lighten up this kind of dull site is a Lamium maculatum (see my answer to Funnyperson, above, for more suggestions).

I would avoid bamboos. If they take hold they may also decide to go for a walk around your garden. The underground stems can travel an awful long way before they reappear - invariably just where you didn't want them to.

General questions

Q. Lexilicious: I'm thinking of career changing into the gardening, home-improvements, energy/water efficiency sort of area. How did you start up your business and build your profile? Do you design gardens for clients and, if so, how much time do you need to spend away from home? Would you recommend blogging and getting 'known' for some cheap work first, then doing things such as RHS diplomas? Or doing the qualifications early then taking commissions at a higher rate?

A. Dawn Isaac: I did courses, but actually started gardening and garden makeovers at the same time. Small jobs, but they help build up your portfolio. But beware of being too 'cheap', it can devalue you and the profession as a whole.

I did do the RHS General Qualification before my Garden Design course and I thought it was brilliant, a great introduction to all areas of gardening and perfect grounding of knowledge on which you can build.

Business-wise, I would get yourself a good logo, website, business cards etc asap. People always check you out online, so your presence there has to scream 'professional' and it needn't cost you a lot of money. Also, take your business cards everywhere - you never know where the opportunities will come - and network like crazy. Blogging and tweeting can help, but make sure you enjoy it because it can also be quite time-consuming.

Dawn Isaac Scarecrow

Q. MrsApplepants: For many years I have been trying to grow hydrangeas, have tried enriching the soil, even planting them in pots with different kinds of compost, to no avail, they never flourish. What's the best way to grow these? Any tips?

A. Dawn Isaac: For me, the secret to hydrangeas is water. Don't get me wrong, they don't like waterlogged soil or permanently wet feet, but they love a rich soil and regular watering. If you're growing in a pot I'd advise a really good size (minimum 30cm diameter and probably more) and very regular watering. You can even try adding moisture-retaining crystals to the compost to help it keep hold of as much water as possible.

Similarly, in a bed, don't let them dry out. This means, plenty of organic matter worked into the soil and keep them out of full sun and wind.

Of course, if you're on a light, sandy soil, you're always going to struggle. In this situation I would heartily recommend going off hydrangeas - and fast. 

Last updated: 9 months ago