Roses are a real sign of summer across Donegal, and in a recent survey by Bord Bia these were chosen as Irelands favourite flower (followed by Lavender, Daffodils and Tulips).
Many of us will have some form of rose growing in the garden, whether it’s a bush, a rambler or a small patio variety in the pot, and these may range from knock-your-socks off scented to half-dead black-spot coated miserable excuses for plants. Well this week I hope to put you on the right path to success with your roses..
by Horticulturalist Gareth Austin
Key Area 1- Positioning
Roses love sunshine. The more sunshine a rose gets the better the perfume. The ingredients that cause the scent are found in the leaves of the plants, the chloroplasts. They are surrounded with glucose which causes them to create the scentless glucosides which are stored or carried to the petals. The scent becomes noticeable if the glucoside is hydrolyzed by an enzyme. This production of scent is a very complex process, which is influenced by many external factors. An important one is the availability of moisture. When the soil is moist, the roses smell their sweetest because the scent ingredient in the chloroplast increases proportionately and is conveyed to the petals in larger quantities. Also roses love fresh air, they like having fresh air blowing around their leaves, taking with it stagnant diseased air and bringing beneficial insects to the party. So a nice bright, open location is best.
Key Area 2- Soil
Roses love a well worked, organic matter rich soil. Or to put simply, they love growing in a soil which is full of well-rotted compost or manure and they love this to be regularly added to. So before you plant roses work in at least 2 big shovelfuls of well-rotted manure (either bagged from a garden centre, or sourced from a horse stable, or cattle shed or the like – we’ll cover this in more detail later) and then in early Spring each year apply a thick mulch of more well-rotted manure (3-5”) around the base of each plant. Don’t dig this in, just layer it on the soil and let the worms and living organisms in the soil work it in. By regularly mulching the roses this will not only feed the plants, but will also supress weeds, improve soil structure and retain moisture in the soil. All this not only helps the formation of scent, but also keeps the plants healthy and in turn reduces pests and disease occurrence. Black-spot, mildew (mildew on roses reduces perfume production) and other diseases which afflict roses can overwinter in the soil in fallen leaves, by mulching you cover over these disease spores, but also create a healthy population of pathogen suppressing bacteria in the soil.
Key Area 3 – Feeding
All this mulching supplies a whole heap of invaluable trace elements aswell as the major nutrients needed for growth, primarily Potassium. This nutrient, which we chatted about the other week, is important for not only the formation of flowers but also in disease resistance in plants. Roses will also benefit from a handful of fertiliser such as Fish, Blood & Bone Meal around St Patricks Weekend and again in mid Summer. Too much feeding and you will get soft growth which is prone to greenfly and disease attack, so try to avoid highly soluble fertilisers and/or tomato food on your roses. The few handfuls and the manure will provide all the nutrition your plants need.
Key Area 4 – Deadheading
We all wish to have roses which produce a succession of flowers, ones which appear month after month in the summer. To do this you have to dead-head as and when the flowers start to collapse. Dead heading roses is a joyful job in the garden, cutting of the flowers just as they fade to a healthy set of leaves, not only keeps the plants tidy looking but encourages the plants to produce more flowers, instead of producing unwanted seed heads. Try to dead head regularly and remove the flowers before they start to collapse and scatter petals everywhere.
Key area 5 – Pruning
I’m a no fuss pruning kind of guy. On my own roses I practice the no nonsense chop. All I do is cut the roses down to half their size in early Winter. This pruning helps to reduce wind-rock caused by strong winter winds, however the date you do this can be influenced by the shelter in your site and of course how late the plants flower upto, but try to have it done by early December. Around St Patricks weekend I then chop them down by another half. I don’t do any angle cuts above nodes, no shortening back weaker stems etc etc…just no nonsense chop, and it works great for me. I learned this from the professional rose growers, they’re pruning many thousands of roses and don’t have the time nor need to meticulously prune every rose plant, indeed I’ve even pruned bedding roses with a lawnmower in high setting with good results. Now this is obviously for bedding roses, for climbing roses we’ll cover them in future weeks. The important thing is that you don’t cut the roses back into ‘old wood’, you must keep your cuts in the fresher green stems, leaving at least 2 nodes on the stems.
Key Area 6 – Pests and Disease
Feeding and soil health, these will be your key weapon in keeping your roses in tip-top shape. Soil that’s not worth jack will give you roses which are mince. Feed your soil, and keep it healthy and you’ll have better plants with better immune systems. The most common disease to affect your roses will be Rose Black Spot, a pathogenic disease spread by rain, wind blown leaves and dirty garden tools. Any temps about 15C are idea for the fungus to spore and spread. A fresh mulch of well rotted manure is helpful to combat the build up of disease on the leaf litter layer, the selection of disease resistant varieties, the cleanliness of your pruners are all essential components in a disease reduction system, add in a fortnightly application of a copper based fungicide and you’ll have the blackspot kicked into touch. Blackspot isn’t spread miles in the wind, if you get rid of it from your garden you’re highly unlikely to have your roses infected by spores carried on the wind from your neighbours, reinfection generally comes from re-introduction – in the form of new bought in plants, infected tools or clothing. So being hard on it for a year or two can lead to it general being a thing of the past in your garden. For pests try to encourage beneficial insects around your roses, so plant some marigolds or some calendula in through your roses, or use a garlic spray to control the aphids, see your previous feature on Home Made Potions.
Key Area 7- Variety Selection
As mentioned about variety selection is not only vital for pest and disease resistance but of course for scent, colour and abundance of blooms. Plant breeders have went to town on roses, you can get nearly every colour under the sun, and these can be found on the Hybrid T, Floribunda, Patio and climbing roses. Perfume is probably the most desirable trait folks look for, however the flowers that last the longest don’t tend to be too scented as the scent is linked to the flowers ripening – if you remove the scent gene the flowers last longer, so it’s a see-saw of trying to get what you desire in your roses. All the good garden centres will have a great selection of roses from Jan-May for immediate planting, and of course there are lots of mail-order businesses, such as the world famous Austin Roses, Dickson Roses and the likes offering countless varieties, so choose wisely and you could reduce a lot of the maintenance moving forward with just choosing the right varieties.
As you can see it’s all about the soil with roses, so bad news if you’ve roses planted through a gravel mulch. In my experience these roses never reach their full potential, as the gravel and membrane prevent you from adding fertility to the soil. If your roses are in this situation and doing poorly, remove the gravel and the membrane, apply some Fertiliser and mulch and you’ll be delighted with the response.
When planting new roses always use the beneficial Mycorrhizal Fungii, this helps the new roses to produce a massive secondary root system, which in turn allows them to bring back more water and nutrients to the mother ship (keeping them pest and disease free), but the use of this will also overcome any rose replant problems, which is a major issue if you replanting a rose garden. The mycorrhizal fungii is something we discussed in a previous feature on Tree Planting. Its great, it works and you should use it when your planting/sowing anything!
We mentioned earlier about using manures. This is something which I was asked about on numerous occasions at the Kees Garden Centre Plant Fair last weekend. All types of manures are beneficial for plants, but some are richer in nutrients than others. The key part is that the manure is at least 6 months old. If the manure has been covered and stockpiled this composting process will kill of weed seeds and will create a more stable source of nutrients for the soil.
Thanks to everyone who came along to Kees Garden Centre Plant Fair last weekend, myself and garden centre manager David Perry had a great time and I was delighted that there were so many folks making reference to this Donegal Daily & Derry Daily piece!
I’m looking forward to meeting more at the next Oakfield Park garden tour which is a Summer Solstice special on the 20th of June, see Oakfield Park on Facebook for more.
Next Week, Growing Tomatoes…the who, what, where of this summer crop….
Gareth Austin is resident Horticulturist with BBC Radio Foyle, a member of the Chartered Institute of Horticulturists and lectures in Horticulture with National Learning Network. For more see www.garethaustin.com or join Gareth on Twitter @GardenerGareth .Tags: