The Garden in July 2025- ‘Everything’s coming up Roses’!
What a perfect way to sum up both June and July? My thanks to the one and only Ethel Merman for putting these words into my head. They came, as I am sure some of you know, from the musical ‘Gypsy’ with lyrics by Stephen Sondheim and music by Jule Styne. Sondheim said later that he was looking to write a new phrase which people would think was an old saying and for me he got it just right!
I write this as we move into the second half of June which will see, as in most recent years, the Old Railway Line’s Rose Festival. This year it will run from Saturday June 21st to Sunday June 29th and hopefully by the time you read this blog you will have enjoyed some of the event and the special offers which were available. To fit in with this event my usual ‘July’ talk was brought forward to Saturday June 28th, the contents of which are contained below.
Before that though, I will just remind you of the past July blogs and their main contents. Back in 2020 in terms of herbaceous plants I was singing the praises of Pentstemon, Hemerocallis (Day Lily) and Hosta and in the shrub section I highlighted Hydrangea, Buddleja, Hebe and Hypericum all of which were performing well in our garden in West Wales. Also, in July 2020 I wrote a separate blog on one of my favourite plants, the ever reliable and versatile Hardy Geranium. In July 2021 I was enjoying all the beauty and colours of the gardens at Aberglasney, including of course, the wonderful display of roses in and around the spectacular ‘Rose Tunnel’. In July 2022 I wrote in some detail about three excellent ‘Summer Plants’- Dahlia, Pentstemon and Salvia. In July 2023 I explored some of the basic principles of garden design with particular references to how roses might be used within such designs. Finally, in 2024 I was again celebrating the wonderful rose with a look at the very special collection of roses in the National Trust garden at Mottisfont in Hampshire and the work done there by one of the world’s foremost rose experts- Graham Stuart Thomas. This blog also contained a section on taking semi-ripe cuttings, including, of course, roses.
Rosa ‘The Generous Gardener’ and an unknown shrub rose in our neighbour’s garden
The lovely rambling, but also repeat flowering, Rosa ‘Malvern Hills’
The climber Rosa ‘New Dawn’ and the simple beauty of the wild Dogrose
Having written and talked about roses several times over the last few years I thought I would do something a little different this year and I begin with an article which I came across in the Daily Telegraph on Saturday 22nd March. Many professional gardeners, and I suspect most amateur gardeners, who have grown roses for several years in the same places, find that their roses don’t always perform as well as they should and eventually deteriorate and die. With this in mind the National Trust recently commissioned a report from top rosarian Michael Marriott. As a result of his investigations at five of the National Trust’s top properties including Mottisfont itself he identified several rose problems which we all face and more importantly suggested possible solutions to them. I think we are all well aware of the symptoms of poor rose health; poor flowering, very little if any new growth, die back where the tips of the stems shrivel and turn black, excessive leaf drop and greater susceptibility to pest and fungal disease attacks.
As with many problems in our gardens some of the above are related to soil issues, one of which is soil compaction as a result of simply walking on the soil over time, a lack of worms or a lack of plants other than roses. Such compaction leads to a lack of air in the soil, poor drainage and the possible creation of a ‘hard pan’, a highly compacted layer within the soil which causes roots to grow sideways rather than downwards making the plants particularly susceptible to hot, dry periods in summer as in 2022 and 2023. His solutions to this problem include forking over the soil between plants to the whole depth of the fork and adding organic matter to help build up the earthworm population. In more serious cases in some of the National Trust gardens the old, poorly performing roses had to be removed and the area sown with a cover crop of Sweet Clover whose long roots break up the pans and absorb excess phosphorus which is removed from the system when the clover is dug up prior to planting up with new roses. In the past, of course, this replanting of roses in an area where roses had been grown before was in itself a problem because of what came to be referred to as ‘rose sickness’. I’m not sure that anyone actually identified the cause but the new roses often failed to thrive and the old remedy for this was to remove the old soil and replace it with new- something which for most gardeners is not feasible. The good news in recent times is that the use of mycorrhizal fungi at planting time along with improving the old soil by adding and working in organic matter is much more likely to result in the growth of healthy and vigorous new roses
The second problem which Michael identified is perhaps a surprising one and is related to the excess phosphorus mentioned above. He discovered that in the five gardens he looked at there were very high levels of phosphates and potash (Phosphorus and Potassium) which were preventing the roses from absorbing essential micro nutrients including iron, magnesium and zinc. This imbalance had been caused by an excess of both chemical fertilisers and animal manures applied over many years or applied excessively. The solution here is to test the soil for phosphates and potash which can linger in the soil for years. If the soil index result is two or three this is good news and means that fertilisers can continue to be used but not in excess. If, however, the index is up at five or six then no more fertilisers containing phosphates and potash should be used until the index has dropped below three which will probably take a few years. However, the other main chemical found in fertilisers, Nitrogen, is still needed for healthy plant growth and can be applied as an organic, slow-release form such as dried blood.
Traditionally roses have been grown on their own away from other plants and while this can look spectacular in June and July for many reasons it is not the best way to maintain plant health. Most gardeners now realise that their roses perform better when either underplanted with other plants such as hardy Geranium, Salvia nemerosa, Nepeta and Lavender or are planted as part of a mixed bed or border. These ‘other’ plants all help to protect the soil from being walked on and compacted, boost biological biodiversity, prevent hard pans developing and improve the resilience of the roses to pests and diseases. Just one word of warning, don’t be tempted to plant too close to the rose base. For most shrub roses say 4 feet (1.2m) in height and width the ‘other’ plants should be at least 1 to 1 and a half feet (30-45cms) from the rose base so that roots don’t over compete with those of the rose.
Michael Marriott’s fourth suggestion as a result of his investigations is to mulch any bare soil between plants with some form of organic matter other than animal manures if the phosphate and potash levels are already high. This protects the soil from compaction by heavy rain and feet, locks in moisture and gradually decomposes adding vital plant nutrients and food for soil microorganisms. He recommends partly decomposed bark as it doesn’t break down too quickly applied at a depth of at least a couple of inches (5cm).
He also recommends foliar feeds such as organic, seaweed-based liquid feed which boosts the immune system of the leaves and although it might contain phosphates and potash they are both absorbed by the leaves and as such they do not reach the soil.
Next, he advises that we all avoid using pesticides which damage the whole ecosystem and in particular the beneficial insects which, if left alone, will control the pests for us. He mentioned the case of one of his own roses which one day seemed to be covered in aphids but by the next day was completely clear. This reminded me of one of our maples in the front garden which in May was being visited by various species of birds as well as by wasps. On closer inspection it had an abundance of blackfly on the undersides of the leaves but clearly as ‘nature’ was dealing with the problem the thought of reaching for a chemical spray never reached my mind. In the words of Michael Marriott ‘just hold your nerve and all will be well’!
Finally, Michael concluded that some rose varieties are simply not robust enough to cope with pests and diseases as well as climate change, excess phosphates and potash and soil compaction especially as they age! His solution is to remove any varieties which are really struggling and to replant, preferably after improving the soil, with more resilient varieties of which there are many now available especially the modern shrub roses many of which have been developed by David Austin and his family.
If you have been concerned that some of your roses have not been performing as well as they have in the past then the above may help you to identify some of the problems which they face and give you some ideas as to how you might address them.
I came across a second interesting article on roses in the June edition of the RHS magazine ‘The Garden’ in which Ambra Edwards looked at the effect of our changing climate on roses in general. This has certainly brought a number of challenges- savage storms, periods of drought and, perhaps above all, mild wet winters. Due to this last challenge our roses are holding onto their foliage for longer through these mild, damp months and as a result the cycle of fungal diseases (blackspot, mildew and rust) is beginning ever earlier in the year. In addition, roses weakened by drought in an earlier hot, dry period are made all the more susceptible to these and other problems. The fact that a rose nursery as important as David Austin has removed from their catalogue such long-standing favourites as Rosa ‘Munstead Wood’ and ‘Lady Emma Hamilton’ due to their poor performance in our changing climate shows just how serious the situation is. However, the good news is that after looking at the constant development and improvement of roses through the ages Ambra is confident that in the longer term with continued exploratory breeding roses can, and will, rise to the challenges of climate change and remain an important part of our gardens. As rose historian Charles Quest-Ritson says, ‘the fact that roses already grow over such a wide geographical area and in such diverse climates shows that they can adapt even to a change of 5 degrees C up or down and with rainfall totals as little as 16” (40cm) a year!’ In the shorter term Ambra confirms what we have discussed earlier, that what will really help to secure the future of roses in our gardens is for we gardeners to grow them well ie. break up hard soil layers, mulch liberally, prune carefully, give them the odd soak in dry weather, not to overfeed and to be prepared to replace them with more resilient varieties when they become old and past their prime and even more susceptible to pests and diseases.
In the same magazine a separate article also caught my eye as it was a plant profile on a type of rose with which I wasn’t familiar- Rosa persica hybrids as well as illustrating why Ambra is optimistic about the future of the rose. As the species name suggests these plants originated in hot, dry places and after many years of perseverance by rose breeders the new hybrids can certainly take the heat in our warming climate. In the article Danial Myhill picks out some of his favourites which all trace back to the species Rosa persica from Iran, Afghanistan and Southern Russia. It is a low-growing, spindly rose with small, smooth-edged, grey-glaucous leaves found scrambling in its natural desert environment- nothing we would immediately recognise as a rose! Its most notable feature is the deep red blotch at the base of each petal which creates an eye in the centre of its bright yellow, single flowers. This feature is unique to Rosa persica and all its hybrids. However, its hybridisation has not been easy and it has taken over 200 years to create some 30 or so garden-worthy hybrids now available in the UK, largely thanks to the work of Jack Harkness and Alec Cocker in the 1960’s. Some of Daniel’s recommendations include Rosa ‘Bright as a Button’ (pink), ‘Angel Eyes’ (semi-double pink), ‘For your Eyes Only’ (salmon pink), ‘Smiling Eyes’ (pale apricot) and ‘Sunset Babylon Eyes’ (semi-double yellow). Not only do these plants like it hot and sunny many have been bred to be disease resistant and the smaller ones are particularly good in containers.
That’s all for this month but I will be back in August with some more gardening thoughts and hopefully useful ideas and plants for you to try out in your own gardens both in the blog and the monthly talk on Saturday August 2nd.
Until then enjoy the first part of the summer in your very own, and I am sure much loved, outdoor spaces.
Keith.