HRAA St. Ives Gardening ClubWednesday 16 April 2014

Gardener’s Question Time Part V

This is Petasites alba (common name - Swiss Mountain Leader). It is an alien to the UK from Central Europe. It is related to our 'Butterbur' - Petasites hybridus which is larger and has pinkish florets.  The photo shows P.alba in it's early flower condition and as the days pass the stem carrying the flowers grows and the flower head thus becomes a spike rather than a 'cauliflower' looking floret. It was well found as it is not common in the UK. It is in the same family as the daisy, coltsfoot etc.

Below

Petasites alba (common name - Swiss Mountain Leader)

Above

Petasites hybridus (Butterbur)

Which small shrubs, preferably wildlife friendly, would be suitable to grow in a bed which faces north-west, but does get a lot of sun in summer?

Here are just 6 suggestions and a bonus:

Deutzia x hybrid ‘Strawberry Fields’

 Family: HydrangeaceaeMax height & spread : 2m (78in) x 2m (78in)  Form: Deciduous shrubSoil: Well-drained fertile soilAspect: Full sun or partial shadeHardiness: Hardy in the British IslesFlower: Summer

Deutzia longifolia ‘Veitchii’

Plant type: ShrubHabit: BushyResilience: HardyFlower Colour: Pink in SummerFoliage: Dark Green and Dark Grey/Silver in Autumn, Spring and SummerSize: Ultimate height 1.5-2.5 metresUltimate spread 1.5-2.5 metresTime to ultimate height: 5-10 yearsEasily pruned to contain heightAny aspect exposed or shelteredMoist but well-drained or Poorly-    drainedAcid, Alkaline or Neutral - Chalk, Clay, Sand or Loam

Symphoricarpus x chenaultii ‘Hancock’

Bushy  ShrubFruits may cause a mild stomach upset if ingestedVery hardyAny AspectFlower White in SummerFoliage Dark Green in Autumn, Spring and SummerFruits Red and White in Autumn Ultimate height: 1.5-2.5 metresUltimate spread: 1.5-2.5 metresTime to ultimate height: 10-20 yearsEasy to grow in most reasonably moist, fertile soil. Tolerant of pollution and all but the most extreme conditions

 

Hydrangea hortensiaBushy ShrubHardiness: Fully HardyFlower colour: White and Pale Pink in SummerFoliage Colour: Dark Green in Autumn, Spring and SummerUltimate Height: 1.5-2.5 metresUltimate Spread: 1-1.5 metresTime to ultimate height: 5-10 yearsAny aspect Sheltered or exposedGrow in moist but well-drained soil in full sun or partial shadeWell-drained or Moist but well-drained Acid or Neutral;  Sand, Clay or Loam

Spiraea × bumaldii 'Anthony Waterer'

Bushy ShrubFully hardy - very cold winterFlower Colour: Dark Pink in SummerFoliage Colour: Cream , Green and Pink Ultimate height: 1-1.5 metresUltimate Spread: 1-1.5 metresTime to ultimate height: 5-10 yearsAny aspectEasy to grow in most moist soils, tolerant of all but the most extreme conditions. Especially suitable for mixed borders

Spireae japonica 'Magic Carpet’

Bushy Shrubhardy - very cold winterFlower Colour:  Dark Pink in SummerFoliage: Bronze, Red and Yellow in Autumn, Spring and Summer Ultimate size: 0.5 - 1 metresUltimate spread: 0.5-1 metresTime to ultimate size: 5 -10 yearsAny aspectEasy to grow in most moist soils, tolerant of all but the most extreme conditions. 

Chaenomeles japonica – Japanese Quince

Growing in St. Ives NE shady aspect, neglected but contained to less than 1 M high. Proves these can be kept compact by simple autumnal pruning

Ticks all the boxes for wild life – flower for pollinators, fruit when softening  for scavengers and good hideaway protection for mini beats 

‘Can annual climbers, such as Ipomoea tricolor be grown up small trees (in the same bed) without causing them damage? What else would be suitable; I am keen to get more height and colour at the back of this bed? ’

Ipomoea tricolor ‘Heavenly Blue’

This is one of the loveliest of climbers, this frost tender annual is easy to raise from seed on the windowsill each year and will twine happily up canes, netting or even small trees. In a sunny place with good soil that does not become parched it will produce hundreds of these exquisite blooms. The silky 7.5cm (3in) flowers are an extraordinary shade of Mediterranean sky blue, each with a white throat, and open from July until frost. 2-3m (6-10ft)

Eccremocarpus scaber (Chilean Glory Flower)

Eccremocarpus scaber (Chilean Glory Flower) are climbing perennials, evergreen or deciduous, with pinnately divided leaves and terminal racemes of tubular flowers.They will need limited support while climbing to branches;Not fully hardy so best grown as an annual;Flower Colour: Reddish orange in Summer and Autumn;Foliage: Green in Autumn, Spring, Summer and Winter;Height potential: 4-8 metres; Spread: 0.5 metres;Outdoors grow in a fertile, well-drained soil in full sun, provide support and shelter from frost

Clematis sieboldiana

Clematis sieboldiana Hardiness: fully hardy

Position: full sun or partial shade Soil: fertile, well-drained soil

Rate of growth: average Flowering period: May to August

Flower colour: white with attractive dark purple stamens

Gorgeous single white flowers which are offset by large, domed bosses of deep purple stamens. The flowers appear in late spring or summer amongst the mid-green, semi-evergreen foliage. An excellent climber for a container or to weave up and through a wall shrub or small low crown tree.

Garden care: Remove dead and damaged stems before growth begins in early spring, cutting all remaining stems back to where strong buds are visible. Apply a slow-release balanced fertiliser and a mulch of well-rotted garden compost around the base of the plant in early spring.

Clematis for Partial Shade, North Walls and within small tree crown structures:

Most Clematis require at least a half day of sun or strong filtered light to bloom well. With a partial shade aspect and cooler conditions with a shorter growing season the following are Species/cultivars are recommended :

Lady Northcliffe; alpina cultivars; macropetala cultivars; Bella Madame; Edouard André; The Bride; Marie Boisselot; Comtesse de Bouchaud ; Mrs. Cholmondeley; Nelly Moser; florida Plena; Pink Champagne; forsteri; Silver Moon; The President; Clematis x jouiniana Praecox; viticella cultivars are but a few which will grow up small well crowned amenity trees or even old Apple trees.

When is the correct time of year to divide up Hellebores? And how are they divided?

With exception of Helleborus foetidus, all Hellebores may be propagated by division during early Autumn. Though seed, collected from parent plants, is often chosen method. Sow in Spring in pots in a cool glasshouse or similar, pot up when large enough to handle and plant out in the Autumn. If division is required because the plant(s) has outlived its space this should be done in early October. Using a garden fork, gently create a fairly large root ball minimising damage to the fleshy roots and gently teasing the complete ball from the ground. Then with either two forks back to back or a sharp knife gradually separate the crown and root ball into two large pieces. With a sharp knife or sharp secateurs cut out any damaged roots. Prepare two planting holes incorporating a good quantity of humus or well broken down compost, add about 2 egg cupfuls of a balanced fertiliser and work into the added humus/compost before planting the new plants. Make sure the crowns are at the same soil level as originally growing, firm and water in well. It may be 3 or even years before the divided plants flower prolifically again. It is for this reason seed is often preferred as flowering usually occurs after 3 years guaranteed.

     Helleborus foetidus best reproduces from seed

         Helleborus hybrids can be divided in October

We have 2 Chimonanthus in the front garden and were planted about 30 months ago and as yet have not flowered can you advise please?

Chimonathus praecox (Wintersweet) is a very sweetly fragrant mid winter flowering deciduous shrub which has small flowers which can be obscured by coarse foliage which has not fallen. Flowers usually occur on well ripened 2 year old stems. All this said to answer the question – this is one of those subjects which can take 5 to 10 years before flowering. So a plant purchased say as a 1 year old plant in 2010 is unlikely to flower before January February 2015 and most likely as late as 2020. Patience is the name of the game. Encourage air and light to percolate the subject, ripen the wood and only prune to remove dead, damaged or diseased wood. Do not cut out healthy wood unless absolutely necessary to contain height and width. Give a late Winter and mid Summer feed of a good balanced fertiliser such as ‘Growmore’, ‘Fish,Blood and Bone’ – giving a good handful sprinkled around the base of the shrubs and raked in followed by a good watering.

Can you help me with a Box hedge problem? – Two sections have started to go a reddish orange colour and their growth is nowhere as good as the rest. I was tempted to replace them with same size plants but feel that will be cost prohibitive.

Box blight enquiries received by charity reach record high (14 March 2014)

Left: Box Blight

The RHS has named the top 10 garden diseases of 2013, based on enquiries received by the RHS Gardening Advice team. For the 18th year running honey fungus is the number one disease, with its presence confirmed on 215 samples, covering 78 plant genera.While it was no shock that honey fungus was the number one problem disease, perhaps the biggest surprise was the influence recent weather had on the list.

The mild, wet autumn of 2013 is thought to be behind a record increase in Cylindrocladium (4th) and Volutella(5th) box blight cases, with enquiries for both diseases reaching their highest levels since the RHS began keeping detailed digital records in 1996.

What is Box Blight? Box blight is a disease of box leaves and stems caused by two fungi, Cylindrocladium buxicola  and Volutella buxi. The two are often found together. This is a disease which largely affects Buxus spp. (box) in the UK, but can also affect other plants in the Buxaceae family.

Symptoms: Both fungi cause leaves to go brown and fall, leading to bare patchesC. buxicola, the more damaging of the two, also infects young stems causing black streaks and dieback. In wet conditions the spore masses of the fungi may be seen on the undersurfaces of infected leaves, white for C. buxicola and pink forV. buxi

 

Control:Unfortunately there is no control other than latent

hygiene. If the disease does break out, remove and destroy affected plants. If they are mature and highly valued, cut out all affected parts, clean up fallen leaves (including stripping and replacing surface topsoil to ensure complete removal) and treat with a fungicide. Do not replant with similar subjects for at least 3 years.  

Is there any way that proliferating species like my Canadian Cornflowers can be eradicated or discouraged without having to double or even treble dig the whole bed?

Is there any way that proliferating species like my Canadian Cornflowers can be eradicated or discouraged without having to double or even treble dig the whole bed?

Unfortunately the following clues from the RHS suggested planting locations and garden types for Centaurea montana (Canadian Cornflower) - Cottage/Informal Garden, Wildlife Gardens, Cut Flowers, Prairie Planting or Coastal plantings suggest this is an invasive character. It not only propagates itself by seed but also by fleshy spreading roots – Rhizomes - which throw up new shoots along each length of root. Unfortunately this means for Brian they can only be controlled by digging up these rhizomatous roots. Unfortunately like dandelions a small piece of root left in the ground will re-grow so it is a case of diligent digging up of roots OR the use of a herbicide. The use of the latter should be via a small paint brush painting leaves of the offending plant(s) carefully avoiding drip on near neighbour plants. It is all a question of balance – digging a small area of a couple of square metres is not to irksome. The problem Brian has unfortunately is 15 M2 or more. A good general purpose herbicide would be best employed if Brain does not want to break his back trying to physically remove these ‘WEEDS’

I have lichens growing on the branches of my apple trees, is this OK? RHS and others say lichens are not a problem just maybe unsightly. No action.

I have heard different opinions on Ivy – [a] that it can kill off a tree if it is growing amongst all the branches from the ground [b] It doesn’t harm trees and is good for wildlife.

Similarly

How does one get rid of wild ivy, without killing the plants surrounding it? My particular problem has two sources: 1) Birds sitting in my privet hedges and dropping the seeds into the middle of the hedge. 2) Creeping growth from a neighbour's garden, at a speed that is like something from science fiction. 

I have tried pulling it out of the ground and treating new growth with soft brushwood killer, with limited success, but, in general, it keeps coming back. Any reduction in vigilance quickly results in an infestation. Talking to people at last month’s meeting, it would seem that unwanted growth, spreading from a neighbour's garden, is becoming an increasingly common problem, especially if the neighbour has moved or died.

Ivy strangles it’s hosts ultimately to their death unless controlled. Try to cut out as much Ivy as you can then apply a strong brushwood killer herbicide to the wound. Cut out regularly and apply herbicide to each of the woody cuts.

Whilst this will not eradicate it will contain and minimise damage to retained subjects.

Having removed the offending Ivy the once hidden and protected woolly Aphids are exposed.

Diligence is the only answer as Ivy will eventually result in the tree being strangled and becoming pest infected.

For the last 3 years this Sorbus tree has been annually cleared if Ivy and is showing a more healthy vigour as Ivy is no longer growing in it’s upper branches. The trunk is much cleaner and the Ivy takes about 10 minutes to deal with each Spring.

Before After

Compost Bin - my new compost bin has what appears to be white flying insects - similar to those laid by a cabbage butterfly - hundreds of them which fly out when I lift the lid.

How do I get rid of them? I don't have any cabbages growing in my garden - the vegetable/fruit  waste peelings etc. are from household  peelings, plus outside leaves of cabbage etc. some twiggy prunings (chopped up), leaves and more recently to try and suffocate the flying insects grass cuttings and then earth.  I have actually sprayed a bug killer too and added Garota powder and water - all to no avail. Any ideas?

I think we may have discussed this problem at our very first question time [January 2012] – Angie Harris had a very similar problem with her compost bins. Any suggestions from our Allotmenteers on this. I think we suggested leaving the bin lid off for a few weeks and possibly capping the top with old carpet or thick polythene and then folding the edges down the side of the compost bin to a depth of 6” / 150 mm.

Question 12 From Pat Edgley

I have recently read that rhubarb leaves are poisonous and therefore should not be put on the compost heap.  Is this correct?  

The leaves of the rhubarb are poisonous (but only if eaten). Left for a few months on the compost heap you will have no problems when using the heap. 

You can also use the leaves as an excellent weed suppressant. just lay them on the ground or maybe the rhubarb patch and it will stay weed free! I am not sure if it is what is in the leaves that does it or more likely the fact that they basically exclude light, control weed activity and perhaps better than just composting.

Simple answer though Pat – Rhubarb leaves do make excellent compost and given you are not going to eat it your compost will not be poisonous to touch !!!!!!!!!

Question 13. From Gerry Swain

I want to move a Camellia from a garden in SE London to my own garden here. I know that this is risky because there camellias grow wonderfully and here is not their normal habitat but I do see them flourishing here. How should I attempt this please? 

Firstly lets take out an insurance and try taking some cuttings from some semi ripe wood about 6 – 8 weeks after flowering.

Gerry also asked whether Tamarisk, Syringa (Lilac) and Forsythia might be propagated by cuttings. They are best propagated by layering but the following technique can be applied to all three subjects

Here goes then :

Camellia – Propagating Step by Step  This is a step-by-step process of propagating Camellia cuttings. This method works for Roses, Gardenias, Azaleas and woody broadleaved shrubs.

1. mix propagation media: 1 to 1 potting soil and perlite

2. Cut a 2 litre clear bottle in half; make holes in bottom; fill with propagation medium

3. 6 – 8 weeks after flowering - cut a fresh limb from the shrub (Mid May - Early June)

     4. Using sharp secateurs or knife, take several 4" cuttings from the limb and trim with clean cuts 3mm below the leaf node

5. Remove the lower leaves, leaving only two at the tip 

6. Dip the end of each cutting into rooting hormone powder, tapping off any excess powder.

7. Insert the cuttings into the propagation medium keeping them about 25mm from the edge

8. Put the top half of the cut bottle onto the rooting chamber and secure with tape;

place in a light but shaded spot for about three months. Late August – Early September

9. Wait until you see a bud form at the tip

      10. Gently remove the rooted cuttings and plant into individual 4" pots; feed with an ericaceous feed ; do not transplant into garden until the pot is filled with roots.

(note that the bottom cutting did not make roots and has no tip bud)

Having taken out the insurance policy we can now prepare to move the parent plant.

Ideally in September/October (but February/March should be okay) look to prepare a root ball in order the plant to be relocated may develop a fibrous root network prior to actual lifting.

Ideally preparation should be a good 9 months ahead of intended ‘move’, a year would be excellent – but some times you may only have 4 to 6 months so long as you do not actually lift the plant during the peak growing season – April to August.

This Camellia was moved via a JCB 11 years ago (2003)

The only downside is that it’s new aspect is due South – not North East the Camellia’s favoured aspect, hence the bud scorch if not by frost by direct sun

The same plant but facing N/E, flowers less damaged and colour less bleached

Our next meeting Wednesday 21st May:

David White, formerly of Dj’s Garden Centre, Chatteris, will give a talk titled ‘A Packet Of Parsley’ (‘A life in horticulture and how it began’) from being the youngest UK Garden Club Secretary to gardening in the Royal Parks before entry into Kew. This will indeed be a warm hearted evening by an impassioned Horticulturalist.