Tuberous Begonias

TUBEROUS BEGONIAS

Tuberous begonias are one of the most reliable summer bedding plants, providing a wealth of large blooms in any weather in just about any colour except blue. They are perfect for bedding, tubs, window boxes, hanging baskets and as a house plant on a sunny window sill. They are also used extensively by exhibitors at gardening and flower shows.

The flowers are usually double and can be frilled and some have a beautiful picotee edge.

Once you have grasped their basic cultural needs for growing and storage they will last for years. I purchased my tubers about fifteen years ago and at the end of each season I have more than I started with as the tubers grow larger. Protect them from frost at all times as they are half hardy.

It is usual to use different varieties suitable for summer bedding (doubles, Non Stop, Frilled, Picotees), those with a trailing habit for baskets (pendulas), and those with large bright flowers for showing (expensive upright doubles). You can pay up to £30 for one tuber of the best variety, whereas tubers for bedding are about £1 to £6 each. They may be expensive to start off with, but they last for years and slowly increase in size.

Early training in Begonias

Away back in the mists of time when the Dundee Parks Dept had numerous apprentices, (here we go again) we were trained to grow begonias to exhibition standards. Our head gardener at Duntrune Terrace training gardens grew them for exhibition at the Dundee flower Show. It was absolutely essential, we were told, to line the inside of the clay pots with fresh cow manure. Apparently only fresh manure would stick to the pots, not to mention the apprentice’s hands. So a wee trip to the countryside was arranged for some unsuspecting young gardeners early in the morning before our ten o’clock tea break. We never forgot how to grow exhibition begonias.

However the begonias were terrific all summer and I needed to get my hands on some for my own garden. An apprentice’s pay does not stretch to the purchase of tubers which at that time cost a fortune, but I could afford a packet of seeds from the country’s specialist grower of begonias, Blackmore and Langdon from Bath. These arrived one January, were sown immediately according to our resident head gardener and I subsequently obtained a small crop of about fifty tuberous begonias. These all flowered that summer and the tubers lasted for years.

History

Plant collectors brought back the first begonia species from Bolivia and Peru in the nineteenth century, but these plants only produced a few small flowers on tall plants. Breeders starting crossing the species, selecting the best plants and slowly over time the begonia began to improve. At the beginning of the twentieth century a partnership of two amateur growers got together and formed Blackmore and Langdon of Bath. They produced hundreds of seedlings to sell to other nurserymen. They also exhibited successfully in London and have continued hybridising begonias ever since.

Propagation

Although cuttings can be taken and root fairly easily, the plant does not produce many sideshoots for cuttings nor are there many initial shoots on the sprouting tuber to take. It is also possible to split the tuber in April when emerging shoots are quite prominent. You need at least one or two shoots on each piece, but this is a very slow way to bulk up stock.

Seed sowing is the best way to produce a lot of plants quickly.

Sow in January to February on finely prepared seed compost. Do not cover the seeds as they need light to germinate, but to retain a moist atmosphere cover the seed tray with glass. Turn this over daily to remove condensation. . They must always be moist, but never wet and need a constant temperature of 65 to 70 F. to germinate. Always water by immersion from the bottom. The seed is very small and the seedlings are equally small, so when big enough to transplant you will need to make a forked stick to lift them out together with a very small dibber. Do not handle seedlings with your fingers. Plant them in trays about 4cms apart and once they fill those, transplant them again into larger containers. Young seedlings are quite tender and may be damaged by strong sunlight, so shade for a few months till they get a bit hardier. They should be big enough to plant out in June.

Culture

Dry tubers are started into growth by placing them close together, concave side up in shallow trays of compost in January or February. Cover them with compost but not too deep. They need a temperature of at least 65 F. Once the sprouts begin to grow and need more space, replant them into larger boxes or pots. Keep them watered and fed. Harden off by mid May and they should be ready for planting at the end of May or early June.

I plant out my begonias in beds at about a foot apart as my mature tubers now grow into quite large plants. They do not need staking, but if you are growing for exhibition you will need stakes as the large flowers are quite heavy.

The plant produces one main large male flower together with two smaller female flowers at the end of each flowering shoot. The smaller female flowers only need to be removed for exhibition. It is not necessary to remove them in a flower bed or tub. They are gross feeders in tubs, pots and baskets and need constant watering, but will reward you with a fantastic show of colour right up till the autumn.

Storing

At the end of the flowering season, about mid October, cut back the plants to about three or four inches and lift them carefully. Knock off any loose soil and store them in an airy dry cool but frost proof place. Let the soil around the tubers dry out and fall off. Store them in boxes concave side up covering them with the dried out soil or old potting compost. Make sure it is fairly dry.

Keep checking them to make sure they are still dry but firm.

Some time in late February the buds will begin to grow, so then it is time to start them back into life.

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Gardening on a slope

GARDENING ON A SLOPE

Dundee town has grown around the Law Hill, Balgay Hill and even Menzieshill, so there is a fair bit of steep slopes incorporated into housing development land.

The challenge of a sloping garden will vary according to the degree of severity, the type of soil and whether the slope runs towards the house or away from it. Slopes can create a dry garden by allowing surface water to run off it, or a flooding problem if you are at the bottom of a hill. Problems of steep sloping gardens are usually left by the builders for the house owner to solve. However if the slope is severe and runs towards the house the builder is most likely to have tackled any potential drainage problem which could affect the property.  However it is always a wise move to check the property to see if there is any history of flooding or water damage.

For every negative aspect of a slope there is always the positive side. You may be blessed with a burn that can create a fantastic water feature garden. A rock garden  is perfect on a well drained slope. Many plants look better if viewed from below e.g. Fuchsias, Lilies, Himalayan blue Poppies, and some better if viewed from above e.g. Tulips.

The slope allows terrific scope for gardening creativity in both soft and hard landscaping so take time to consider all aspects before getting the spade out.

Drainage

If your garden is at the bottom of a slope, surface water causing local flooding after heavy rainfall could be a problem. Wet soil may be indicated if you see a lot of moss, sedges or buttercups. It may be sufficient to cultivate deeply to allow water to percolate through the soil, but if the flooding risk is high consider some garden drainage. This could be a simple drainage system of perforated pipes under a gravel path leading to a decent sized soakaway. A more ambitious project may be necessary with professional advice needed on depth, type and size of perforated pipe, backfill material, extent of run and connection to an outlet. If using a surface water outlet the connections are critical and must be done properly incorporating a catchpit so that garden silt or debris can be filtered out in a sump to be cleaned out periodically.

Access

After drainage, good access must be incorporated into the design to allow for weeding, planting, pruning and wandering around enjoying the garden. There must be plenty of flattish areas to work from connected by a path network. Strategically placed large bushes and trees can help to hold onto to assist stability. Footpaths on very steep slopes are best with a handrail for safety.

A path system may be formal with slabs, bricks, and breezeblocks, or it can be sympathetic to the landscape with natural wood risers backfilled with course wood chips. A trip to a builders merchants yard who specialises in hard landscaping can give many ideas to work on.

Retaining Walls and Terracing

Really steep banks may require retaining walls next to footpaths, but terracing with large rocks will give a more natural appearance. Good quality natural stone can often be acquired from builders yards if they have been doing any demolition of old buildings, or it may be purchased from a local quarry. The size of the job will determine whether it is done in house or whether a bricky or stone mason is employed. There are plenty of excellent dry stone wall builders who can create an attractive wall with strength. If cost is a factor breezeblocks can be used for speed and strength. Their formal appearance can be softened with ground cover plants allowed to trail over the edge.

Make sure any walls are strong enough to retain the bank for at least 50 years and provide weep holes for drainage.

Terracing is very useful to break the bank into a series of flat areas held up by as big rocks as you can find. During garden maintenance you will want to scramble over these rocks without fear of them toppling over, so size is important. A JCB may be needed to move big rocks around. Try to create a series of natural looking rock faces with the rocks relating to each other. Bury at least two thirds below ground. Create a series of plateaux  by cut and fill over the slope.

Decking

This can be an important option to create a flat patio adjacent to the house on a steep bank. Often there will be space left below the decking as the slope falls away. This is useful for storing garden tools or given over to the kids as a den to play in. Much safer than a tree house.

 Make sure your patio enjoys plenty of sunshine, some privacy and shelter from winds. Decking has been in fashion for a few years now, so there is plenty of information on materials, construction methods and maintenance of the wood. Make sure it is strong, the wood is well preserved and the design safe.

Plants for soil stabilisation

Once the slope has been hard landscaped, the planting can now be thought out. Terraced slopes and walls allow a fair bit of easy planting at waist height, so these areas can be more intensively gardened. Other areas of steep slope may be better with permanent planting, choosing plants that can hold the soil together to prevent any erosion.

I garden on several very steep banks with a fair degree of walls and terracing. Over time some plants prove much better than others in binding the soil surface together.

My favourites include Flag Iris, Delosperma, heathers, London Pride, Euonymous, variegated ivy, numerous dwarf spreading conifers, Shasta daisies, fuchsias, rhododendrons, azaleas and hostas.

For the larger garden use philadelphus, saskatoons, ceanothus, viburnums, kerria and cornus.

It always helps if bulbs can be interplanted as they can be very good at naturalizing. Bluebells and grape hyacinths are some of the best.

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Perfect Gardening Weather

 PERFECT WEATHER FOR THE GARDEN

Spring has been perfect this year. We had enough dry weather to catch up on outstanding tasks, complete the digging, and start the planting and sowing. Then the sun came out for a whole week and just as we were beginning to worry about the soil drying up, along came some serious rainfall.

The spring flowers were glorious and tulips have never lasted so long. The strawberries are two to three weeks ahead of last year and I have harvested my first lettuce and radish, and the sun lounger has been tested on several occasions. Well, I have to do my garden planning somewhere.

Every time I need to crack on with a bit of planting the weather turns dry, then once I’ve finished we get a bit of rain over night to water things in. This is just too perfect.

Is nature trying to make up for giving us two hard winters on the trot plus three wet summers. We lost a few plants in the winter, including some cistus, escallonias and cordyline, but those that survived are really putting on a brilliant display. My Fuchsia Mrs Popple was again frosted back to ground level, but it has survived and now has many young shoots reaching for the sun.

Flowers

The spring flowers will now be replaced with summer flowering bedding plants. Tubs, hanging baskets and beds have now all been replanted with geraniums, tuberous begonias, petunias, nemesia, busy lizzies and lobelia.

I grow some cosmos which is used to fill in any bare patches around the garden, and also sow some Shirley poppies which never fail to put on a good show.

Euphorbia polychroma has lovely lemon yellow flowers, but this year they are quite dazzling.

Azaleas are at their peak and really enjoying the moisture combined with cool but sunny weather.

Lilac is also superb with the white Mme Lemoine still favourite, and the deep lilac Michel Buchner also outstanding.

Himalayan blue poppies continue to flower, but remove the seedheads unless you wish to increase the stock. They grow fairly easy from seed if harvested when ripe and stored in a fridge for a few months. Sow them in a tray in late autumn and keep them outdoors all winter in a sheltered but shady place. Do not let them dry out and they should germinate in April the following year.

Iceland poppies also need regular dead heading to keep them flowering all summer. I also save the seed but sow them in late summer so I can overwinter small plants in trays for planting in early spring. These will then flower for the next two years.

Aconites grow quite easily from seed, so collect it as they ripen and sow it immediately where ever you wish to grow them. They naturalise rapidly.

Fruit

Apple and pear grafts are now shooting so I will soon have new varieties on two trees. I am looking forward to seeing pear Beurre Hardy and Christie and apples, Park Farm Pippin, Lord Roseberry and Pearl.

Mildew on apples overwinters in buds which open up in spring completely infected. These primary infections are quite noticeable, (they are completely white with mildew) so they should be picked off and destroyed before they spread.

Peach fruit set has been really poor. I think the severe winter did not help them. The blossom was quite late to open, (normally a distinct advantage), but never looked very strong, and although they got their regular hand pollination, assisted by a few bees most did not fertilise. They did not get any late frost. I hope to get three fruits this year and they will still be better than supermarket peaches.

Fig bushes got a fair frosting, killing back many shoots, but there is still a wee crop.

Allotment

All my fruit bushes are looking very good, but the gooseberry sawfly caterpillars have massed an attack. I spent an unpleasant moment picking them off and disposing off them. You need to be vigilant as they don’t hang about. They can chomp through the bushes at an alarming speed.

Strawberries are looking great and I may be picking my first fruit by the time you are reading this.

Planting has gone ahead at full steam. Sweet corn, cabbage, cauliflower, Brussels sprouts are all planted and seeds of Dwarf French beans, Swiss chard, lettuce, radish, spring onion, beetroot, turnip, and Swedes are all sown.

Leeks have germinated but are quite slow to grow.

Glasshouse

Tomatoes have established in the growbags and are now in flower, so feeding has started. The flowers get a daily tickle to spread the pollen which will assist fertilisation as the flower is cleistogamic. Just love that word !!! Google knows what it means.

If you are growing them as cordons, remove the sideshoots regularly and twist the growing stems around the supporting strings to keep them upright.

Grape vines are now showing the flower bunches. I cut back any non flowering shoots to a couple of leaves just to help feed the plant. The flowering shoots get cut back to two leaves after the flower bunch. Thereafter right through the growing season you must cut back all sideshoots regularly to one leaf. Black Hamburg is very reliable and is full of flower, but Flame, my red seedless variety and Perlette the new white seedless grape do not have as much flowers as I would like.

However my newly planted outdoor grape vine, Solaris has a couple of bunches on it. Gardening by the book, I should really remove them to let the new vine concentrate its energies into growing into a strong bush. I was never very great at doing the right thing and I am very curious to know if I can get a good outdoor grape to ripen in Dundee, so I may leave them alone for a bit, but keep the situation monitored. My outdoor Brant is very successful, but it has small bunches that are not very commercial, no matter how sweet and juicy they are.

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Rhododendrons and Azaleas

RHODODENDRONS AND AZALEAS

The first rhododendron I came across was R. praecox growing in a large drift in a bed of pure leafmould. This was at Dawson Park in 1960 when the park was in its early years and was not much more than a playing field with a few interesting plants to relieve the boredom. I won’t ever forget my first two years apprenticeship training, digging drains all winter at Dawson.  The highlight of the year was when that rhododendron flowered and that only lasted a couple of weeks, but it must have made an impact on me as I have never been without my R. praecox. It is one of the first to flower usually in March or early April but only if there are no frosts to shrivel up the delicate mauve flowers.

The following year I was working at Camperdown Park where mature rhododendrons grew all over the place. Training trips in spring arranged for the apprentices by our tutor Walter Gilmore took us to Edinburgh Botanical Gardens and Crarae Gardens where both Rhodos and Azaleas are grown on a massive scale but to perfection. I was hooked for life. Parks training helped me understand the range from the tall varieties to the dwarf evergreens and the deciduous azaleas, and that first bed at Dawson growing in pure leafmould made me realise the importance of giving them the correct type of acidic soil.

Today we do not have to go too far to see them in all their glory growing in natural surroundings covering the whole spring season. The gardens at Glendoick are now world famous as the place to visit to see hundreds of different rhodos, azaleas, camellias and numerous other woodland plants growing in a natural setting of a Scottish glen complete with a burn and waterfalls.

History

No article on rhododendrons and azaleas would be complete without some reference to the massive contribution made by several generations of the Cox family.

In the early nineteenth century the Cox family started a textile business in Lochee. This was consolidated by four Cox brothers in 1841 and the factory at Camperdown Works was reputed to be the biggest jute factory in the world employing 5000 people. Alfred Cox bought Glendoick House and estate in 1899. His son Euan, educated at Rugby and Cambridge, got a taste for the good life while working in London and had little enthusiasm to return to the jute business in Dundee.

A chance meeting in London with the plant explorer Reginald Farrer led Euan to join him in his first plant collecting expedition to Burma in 1919. The trip was a great success and many new rhododendrons and other plants were introduced. Euan loved to write about the new plants being introduced from all over the world and founded a bookshop in London. However this got bombed during the war and Euan returned to Scotland to help run the family jute business. He started to develop the gardens around Glendoick with his new seedlings from his expedition. He also subscribed to other expeditions and received many new plant introductions. A nursery was started with new plants acquired from other collections. Then his son Peter started to go on plant collecting expeditions to Turkey, India then China in 1981. The garden at Glendoick expanded up the burn.

The rhododendron nursery was established in 1953 and the garden centre in 1973.

Peter’s son Kenneth has maintained the family traditions with 9 plant collecting expeditions and written many horticultural books. Peter and Kenneth have been breeding rhododendrons for over 50 years to produce plants suited to small gardens and the Scottish climate.

For the full and fascinating story of Glendoick, the Cox family, and their involvement with rhododendrons and plant exploration, check out the website at www.glendoick.com.

Types and varieties

Most Rhododendrons are evergreen but the Azaleas may be evergreen or deciduous. They come in all sizes from a few inches tall to small tree sizes given time. Many of the deciduous azaleas, eg A. luteum are scented. The flowering season normally runs from April to June, but changes due to weather pattern at the time, and there is always a few types that will flower early or later throughout the summer. R. praecox can flower in late March but the flowers are not frost hardy so can get wiped out in a bad year.

If you have a large garden you can indulge some of the taller growing varieties such as Cynthia, a vivid scarlet, Pink Pearl, or Horizon Monarch a yellow with red buds.

For smaller gardens try Nancy Evans, a deep yellow, or Elizabeth, a brilliant red that has been a favourite for years.

Azaleas tend to flower a bit later, but many have an exotic woodland scent and orange flowers such as Gibraltar. Klondyke is a brilliant yellow and there are numerous others in reds, pinks, mauves and white.

Dwarf evergreen azaleas (Japanese azaleas) may only grow a couple of feet or so after ten years, but they are perfect for mass planting for ground cover. They are also very easy to propagate from cuttings. Glendoick have bred numerous new varieties in colours including pink, purple, scarlet, white, orange and crimson.

Site soil and planting

Most Rhododendrons and azaleas flower better in full sun in Scotland as we don’t suffer too many very hot summers. They associate well as woodland fringe plants with a backdrop of birch, rowan, pine, spruce or if you wish a flowering tree choose a cherry or Eucryphia Rostrevor. However make sure they are not shaded by the canopy.

An acid soil is a must with all of these plants. Fortunately most soils in this area are naturally acidic, but may have been limed for previous crops. They like a free draining soil that can hold moisture. Soils can be improved by digging in plenty of leafmould, composted bark, garden compost, pine needles or peat. Acidity can be improved by using sulphur chips and a pre planting light dressing of sulphate of ammonia and sulphate of iron, but not after planting as they may scorch young leaves.

Plant rootballed plants in the dormant season, but containerised bushes can be planted at any time provided they are always kept moist. Do not plant deep and any mulch should only be quite shallow as the fine surface roots do not like getting buried.

Rhododendrons and azaleas do not need much feeding, so a light annual mulch will be quite enough.

Pests and diseases

Mildew may be a problem on a few varieties, (Elizabeth is prone) but can be controlled with a fungicide used for rose mildew.

Azalea leaf gall, exobasidium, can be a problem on the Japanese evergreen dwarf azaleas. Pick off and destroy any galls as soon as you see them.

Vine weevil adults cut notches around leaves and can girdle the stem just above ground level. They produce white grubs that eat the roots.

Lime induced chlorosis is only a problem where the soil is not acidic enough.

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