Garden tips April
This week is National Garden Week (11-17 April), so if you haven’t ventured out to tend your plot of weeds and brambles, get out there between hurricanes and start digging. Don’t forget the suncream though yeah?
This month’s garden expert handing down the knowledge is head gardener, and International Camellia Society Director Gary Long from Trewithen Gardens in Truro. Trewithen means ‘house of the trees’ in Cornish – with acres of surrounding woodland gardens and parkland, the name couldn’t be more appropriate. As well as being one of the six great gardens of Cornwall, Trewithen is also one of only five ‘International Camellia Society Gardens of Excellence’ in the UK and one of only 50 in the world!
Over to Gary…
Little and often
We have a modest garden of 30 acres here at Trewithen so cannot physically do everything at once – you’ll find this even if you have a typical sized garden. Regularly hoe beds to remove weeds and also to help prevent weed seed germination by continually moving the soil. Pulling tree seedling out while they are small and easy to handle is far better than waiting and paying, for a tree surgeon to remove unwanted trees in the future. This time of year it is fairly easy to identify the tree seedlings as they produce their first pair of true leaves.
After you have cleared the beds or borders of unwanted weeds apply a thick layer of organic matter. We use a combination of well rotted (at least 18 months on and with no smell!) pony manure mixed with our own garden compost and again (well rotted) wood chippings. Apply a good thick layer at least 5 cms plus around the base of the plant all the way out to the natural drip line which is sometimes a bigger circle that you first think. When applying organic matter be really careful not to go too close to the stem of the shrub/tree (though herbaceous plants aren’t too fussy) as you could effectively ring bark the plant.
Rhododendron are notoriously fussy when it comes to mulching. A lot of the Genera are epiphytic growing on instead of in soil. We plant them slightly raised, mounding up the soil to improve drainage (another bug bare of Rhodo is poor drainage) and if we mulch we leave a clear ring of 10cms away from the stem.
The number one top tip for good compost is “Turn it”. Build up the compost in thin layers and ideally turn once a week. The air helps create an “Aerobic” atmosphere within the compost speeding up the process and generating a great deal of heat (If you can comfortably leave your hand in the centre of your heap you are doing something wrong, you should see a plume of steam from the heap when you turn it).
We have over 200 varieties of camellia at Trewithen, and the best time to hard prune spring flowering varieties is when they still have some flowers on. The whole plant is “dormant” while in flower. As soon as flowering has finished the sap starts to move and the new growth will begin. Pruning before the new growth starts stops the plant wasting energy. We use a technique called “Hat Racking” which involves removing ALL stems back to the main frame work of the shrub, like a hat rack. Nothing will happen for at least 6 to 8 weeks, where a slight panic might set in but be patient and wait for the boom! The main stem will become covered in tiny dimples, growing into new shoots and fully flowering within 3 seasons. The plant will thank you for it.
Done at the wrong time the camellia will be very slow to recover. An example of this happened in 2005 when we had snow! Very rare in Cornwall but it caused a couple of plants to collapse under the weight. We had to prune the camellias, hard, in November. It took over 5 years before the plant flowered and then a couple of more to fully flower.
The moral is “pruning, don’t be afraid, the worse you can do is kill it” 🙂
Pest and disease watch
Keep an eye out for bracket fungus on trees as they become more visible at this time of year. Usually it’s never good news when the fruiting body, the mushroom/fungi, is visible because most of the damage will have already been done inside the stem of the tree. If the tree is in poor health it is worth calling in a tree surgeon for a professional opinion.
Protect new plantings
Here at Trewithen we “Cage” all new plants with chicken wire and bamboo canes. After planting, labelling and entering the plant onto the data base we surround the plant, leaving a good gap to allow for growth, with a ring of chicken wire. This is helps to stop stem damage form grazing rabbits, deer and in our case, hare. Leave the cage in place for up to 12 months then move it on to another new planting. We find the hare only cause damage on newly disturbed soil i.e. after planting and will leave plants well alone once established (also hare don’t like Rhododendron but love Camellia!).