Thanks so much to the very excellent and knowledgable Diarmuid for his time - it’s much appreciated! There are extensive show notes written by Diarmuid for this episode below.
Can you grow anything in pots – plants and trees? What can I grow in pots now?
With good care, there’s a not a lot that you can’t grow in pots. This is indicated by a visit to any garden centre where trees, shrubs, flowers bulbs and fruit trees are all in pots. Or think of roof gardens. Google Derry and Tom’s roof top garden which was on Kensington High Street and you’ll see the images of mature gardens with trees and shrubs, all growing on top of a building with very little access to soil.
What you have to consider for anything big is where the pot or containers is going be placed and if you are using a tree such as birch, beech or Carpinus, are they anchored well because you don’t want them rocking around. Secondly they’ll be growing in the pot soil for a long time so make sure you give them really good soil from the start. Drainage is really important - roots of plants needs oxygen as well as water. So make sure that there are good drainage holes and some layers of pebbles at the base. Don’t let the containers dry out during the summer. And for anything that is going to be living in that pot for a long time, top dress it annually. This means gently removing the first couple of inches of compost or soil from the top and replacing with fresh nutrient rich growing medium every year.
Is it okay to grow Prunus x Cistena in a pot please?
This is also known as the purple leafed sand cherry and is a medium sized deciduous shrub with pretty spring blossoms and attractive purplish-red foliage. It won’t grow much taller than 5 feet so should be fine in a large pot.
Planning a new bed that’s 100% shade – what do I plant please?
Even the thought of a dark damp place and I immediately have ferns in my mind. Ferns conjure up feelings of a leafy woodland floor, of a trickling stream under a dense tree canopy. There is nothing like the unravelling of their brown hairy fronds that open up into bright green lacy leaves breathing life into every corner. Dryopteris filix-mas or the Male Fern is one of the oldest ferns in existence and one of the most beautiful. Its leaflets are deeply toothed and they can remain standing all through the winter in milder locations. They are elegant yet robust and tower at almost a metre high. Woodwardia unigemmata is lime green with large gracefully arching fronds and Polystichum setiferum is wonderfully tactile with intricately toothed, almost fluffy fronds.
Ferns sit beautifully next to the elegant evergreen heart shaped leaves of Epimedium ‘Sulphureum’ that are joined by sprays of bright yellow flowers in the spring on tiny fine stems. Other epimediums have white and pink flowers and fantastic bronze foliage.
I find these very useful under the dry shade of my front garden birch trees, alongside anemones, pachyphragma and bluebells. Another small plant that can carpet a shaded area to perfection is Trillium chloropetalum, an absolute jewel in the shade. Upstanding flowers in shades of wine sit directly on leaf rosettes in sets of three that display varying degrees of marbling.
If you have large areas to cover under tree canopies, the large heart-shaped and deeply textured Trachystemon orientalis can quickly form a dense ground cover and are useful plants for strong contrasts with other shade plants. Interplant with Erythronium ‘Sundisc’, a bulb with reflexed yellow flowers on tall brown stems that naturalises wonderfully or with Polygonatum x hybridum (Solomon’s Seal’), another bulb that thrives in the shade. Tall arching stems with deep green leaves that dangle white bell flowers on their underside throughout May create a real surprise in a shady area.
I’d like my wildflowers in one of my raised beds this summer – do I plant seeds or just buy plants?
There’s two primary ways that you can grow what we term wildflowers. Suppliers who grow turf for lawns and football pitches will often also grow wildflower turf which can be rolled out so if you have a local supplier who does this that’s an easy option.
If not, they are so simple to grow from seed. Make sure your raised bed is in a sunny position, strip away anything that will compete with the seedlings as they emerge such as bits of grass or weeds. Lightly rake over the surface and sprinkle over the seed mix. It’s up to you which one you get – native wildflowers are wonderful pollinators but not as showy as some of the bright meadows we see. If you’re in the countryside I’d suggest you stick to natives so there’s no chance of colonising your area with species that may take over.
Why do I never get flowers on my camellia?
The buds for this year’s flowers formed last summer and if your camellia is drying out during the summer, for example in an unwatered pot, the buds may have shrivelled up and hence no flowers. Excessive and late feeding can also cause buds to die so don’t feed later than mid-summer.
What to plant around a brand new gravel path?
The plant I’d go for to frame both sides of the path is lavender. It loves a free draining situation such as this in full sun and a successful small hedge of lavender could look like something from a Jane Austen novel. If however your soil is heavy you can get the same effect by using Nepeta, also known as catmint – this also has pale blue flowers and minty smelling foliage that will be gorgeous to brush past on a path.
What are the best plants for open exposed borders?
If you think of open exposed sites in the natural world and that will often bring you to coastal places. So choose some plants that have evolved to grow in windswept locations where they may have the added challenge of salt laden air. Often plants with a silvery hue created by hundreds of microscopic hairs over the foliage will do the job so think olearias, astelia, rosemary (especially the ground hugging variety), escallonia and elaeagnus or toughies like holly and birch and mountain ash. A lot will depend on your soil type. If it’s a spongey bog, mimic the highlands and plant heather.
What are your top tips for creating structure so that a herbaceous border doesn’t spend half the year as a sea of mud?
A herbaceous border is generally made up exclusively of herbaceous plants which die down from late autumn to spring. What you’re looking for is a mixed border which is a very sensible solution especially for smaller gardens. The trend of the moment is topiary cut into pin cushion or spherical shapes dotted through the length of the border which allow the flowers, bulbs and grasses to grow up around them. But you could also try other evergreen shrubs such as Pittosporum tobira Nanum, some viburnums, or maybe Heavenly bamboo, Nandina domestica. That will provide a good mix and may also give a structure for some of the taller herbaceous plants that may otherwise need staking.
Ideas for planting on a strong slope (over 45% in places) with cold tolerant plants.
Planting on a slope brings its own complications. “Mini-terrace” while planting so the plant is standing straight up, not sticking out at an angle. The advantage of the slope is that it displays the plants very well, in a much more interesting way than a flat site.
If the slope is in an open sunny position, you could choose a single species such as a bank of lavender – this will require an annual clip when flowers are spent but you will be rewarded with a glorious swathe of lavender blue flowers and scent in the summer. Intersperse with ground cover hardy geraniums such as Rozanne that provide lots of flowers throughout the summer period.
Vincas do a great job of knitting the soil together as they creep along and they are some lovely bloomers such as Vinca minor Bowles variety which will act as a great weed suppressant.
Flower carpet roses are very vigorous and are prolific bloomers and you can choose from pinks, reds and yellows. These have been bred to do the job of carpeting an area and are disease resistant. They will require an annual trim and feed but that’s about it. The bare root planting season is approaching which is the cheapest way of planting a lot of roses so you could put your order in now and start preparing the soil.
If you prefer a naturalistic look, I’d probably plant a mixture of ornamental grasses which provide a long season of interest and can look very attractive in winter as well. These only need a cutting back in spring though will need division to keep fresh as the years progress. A good mix would be some tall Stipa gigantea, Imperata cylindrica ‘Rubra’ with its ruby red tips, Calamgrostris Karl Foerster, Molinia, and Hakonechloa.
What to do with tulips that have been in the ground for years and only produce lush leaves?
I would dig them up and throw them out. Most of the tulips we plant are highly bred and often only perform really well for one year. Those that do reflower are often smaller or paler. However, if you buy species tulips such as the lovely Tulipa humilis, they will naturalise and perform as perennials, returning in flower every year.
How can I stop Japanese Anemone spreading – it’s taking over?
First of all, can we take a moment for this plant. It’s a very handy plant for a dry situation. I have it in dry dappled shade underneath birch trees and it’s thriving. When it’s in flower it’s a delight. Prevention is the best method, in other words anticipate the problem before you plant and install a root guard so it can’t escape – this is a barrier underneath the soil which keeps your anemone roots confined. But if it’s already spreading, then it’s just old fashioned elbow grease required and digging out the clumps with a spade.
Is there anything you shouldn’t prune? Chopping stuff back scares me.
Pruning is a dark art! You prune for shape (think topiary), for productivity of flower or fruit (think apple trees or roses), for health (it’s important to take out any dead and diseased wood) and for convenience (for example, espalier pears pinned to the boundary of a walled garden when there’s no other space available). But let me tell you a secret… there are piles of plants that will do just fine if you don’t prune them. They might not maximise their potential in terms of flower or produce and may look a little untidy but they’re growing as nature intended. So don’t feel you always have to be pruning. A few rules of thumb to know: conifers don’t regenerate if they are cut back hard, with the exception of yew and avoid chopping back spring flowering shrubs such as forsythia until after they have flowered otherwise you will miss all the lovely flowers.
Not really garden, but decking care please.
Decking care is all about choosing the right material and the right position for the deck. A deck is going to require firstly, an open sunny spot with great air circulation. If you don’t have that you shouldn’t install a deck in that position. Secondly good quality material and a credible installer whether that’s a contractor or yourself. Depending on the site a weed barrier may need to be put underneath. If it’s softwood it may need treating every year. If it’s hardwood only sustainable wood should be used. Increasingly growing in popularity are composite decks, often made from recycled materials and they can require less maintenance. Deck maintenance involves power hosing it every year and maybe applying a preservative, depending on the type of wood. Western red cedar and larch won’t need this.
What can I do about a waterlogged lawn?
We have had a lot of rain, more than usual so even good functioning lawns are saturated. However, your problem may more severe. If your lawn is waterlogged it means the base material on which the lawn was planted is most likely compacted. You often get this in new build houses where heavy machinery has been driven across the gardens before they were gardens and then a skim of top soil spread over them. As with any other plant, the lawn’s success will depend on what it is growing in and to repair this could be a big job. At a minimum, this will be rotavating the lawn to a substantial depth and adding in plenty of good quality free draining top soil before re-turfing or re-seeding the lawn. If it’s very bad it may require installing some drains which is most likely a job for an expert.
Getting rid of moss in the lawn after winter and a lot of rain?
I’m going to start by being facetious - why do you want to get rid of it at all? We’ve turned moss into an enemy and if it’s happy in your situation it means it’s growing in a viable place to sustain it and will be nice and soft and green much of the time. If you’re determined to rid yourself of the dreaded moss, you may have to install drainage to make your lawn drier and less hospitable to moss. The other aspect to this is that lawns only thrive in open sunny positions so if you look closely you may find that your moss is growing in the shaded part of the lawn.
Clover lawns? Yes or no?
Even the fact that the question is being asked is being wonderful as it indicates an openness to get away from traditional lawns which have dominated our towns and suburbs for hundreds of years. A clover lawn could be a great idea depending on how you are going to use it. Clover is a ground covering plant which flowers in summer and it’s quite delightful. Its form can look like a small field of mini hillocks. The flowers will attract all sort of pollinators and it has a wonderful smell however if you fancy a roll in the clover you might get stung! It needs little maintenance – certainly no feeding and just a light mowing every so often.
How do you hide an ugly shed in a smallish garden?
I’d plant it. The issue with sheds and other structures is that by trying too hard you can end up drawing more attention to it. Treat it as a host structure for climbing plants, for example Hydrangea petiolaris which is self-clinging and won’t need any framework. If it’s in a sunny position, you could coat a face of the shed with chicken wire and plant sweet pea to ramble through it. The scent will be wonderful. With a heavier trellis on it you could use it as the base for a small climbing rose such as ‘Gertrud Jekyll’ which also has great scent. Or if you want a fast solution, consider a Clematis montana which will ramble over the structure in no time at all.
I have a fig tree that fruits small figs that are inedible – I want figs that I can eat. How do I do this?
The best figs are those baked by a Mediterranean sun which gives them an intense sweetness. So firstly, make sure your fig is in the sunniest spot you have, trained against a south facing wall is ideal or in a conservatory. Secondly, the variety – ‘Brown Turkey’ is considered the hardiest and best performing for the UK but taste is so personal you could try other varieties that are hardy here such as ‘Brunswick’, ‘Rouge de Bordeaux’ and ‘Violetta’.
With many thanks again to Diarmuid for his time! Hope you enjoyed listening and reading and stay tuned for more podcasts coming very soon.
In Conversation With: Diarmuid Gavin, Garden Designer