Mandy, Planting, Plants

planting azaleas

Rhododendrons and azaleas are extremely popular, despite their reputation as being tricky customers! However, by avoiding these basic mistakes, you’ll have beautiful shrubs with spectacular flowers, whether they are for a Japanese-style border or as the year-round evergreen backbone of your garden.

Soil Type

This is the number one cause of failure. Rhododendrons and azaleas need acid soil to thrive (between pH 5.0 and 6.0). If you don’t know the pH of your soil, you can buy simple home test kits for a few pounds. If your soil is alkaline, choose compact varieties and grow them in containers in ericaceous compost – reducing soil pH is difficult. The soil needs to be well-drained but rich in acidic organic matter – dig in composted tree bark, leafmould, decomposing conifer needles, or composted bracken.

Planting Problems

Avoid planting when the rhododendron/azalea could get waterlogged in winter or dry out in summer – October or March/April are ideal times. Don’t plant too deeply, as members of the family are surface-rooting and the roots should be just covered. Apply an 8cm-deep loose mulch of chipped conifer bark or other acidic organic matter. Renew the mulch each spring.

Growing in Pots

The only way to grow successfully if you have alkaline soil. Use the biggest pot possible and John Innes ericaceous loam-based compost. Plants will need to be carefully watered and fed. If you’re using soil-less or peat-free potting compost, they can lose their structure, leading to poor drainage, causing leaves to brown and die back. Repot every other year into fresh compost in early spring and replace the top 5cm of compost in between.

Size and Leaf Type

Not doing your homework about your chosen plant’s eventual size can be disastrous. There are tens of thousands of rhododendron and azalea varieties, ranging from dwarf alpines to massive trees.

Two popular RHS Award of Garden Merit winners demonstrate the difference –  R. macabeanum is an evergreen tree with cream/deep yellow flowers, 30cm long leaves and an eventual height of 15m and spread of 6m. Meanwhile, R. ‘Ptarmigan’ is a spreading dwarf shrub with dark green leaves and white flowers, height and spread 1m. Read those labels!

All rhododendrons are evergreen but there are two distinct types of azaleas. Evergreen azaleas (Japanese azaleas) typically grow to 40-80cm. Deciduous azaleas reach 120-150cm and lose their leaves in the autumn, often with stunning colours.

Placement

Choose a sheltered site with dappled shade but avoid deep shade beneath trees. Dwarf alpine species will cope with full sun as long as the soil does not dry out. Avoid frost pockets and sites exposed to early morning sun, which will damage flower buds.

Watering

Even though rhododendrons grow best in areas of high rainfall, soils need to be well drained. They like moist soil, not sopping wet mud. This airless mass will lead to root rot and will kill your plant. To avoid overwatering, use your hands – stick a finger in the soil. If it’s moist, leave well alone and check again in a couple of days. Don’t kill with kindness.

Tap water, especially in hard water districts, reduces acidity around rhododendrons’ roots.

Use rainwater for watering rhododendrons and azaleas, but if your water butts run dry, tap water is better than nothing for a month or so in summer.

Wrong Fertilisers

Using the wrong fertiliser can lower the soil’s acidity; don’t use lime or other alkaline-based additives. Keep the soil’s pH level to about 5.5. Try to use organic fertilisers, as rhododendrons are susceptible to chemical burn. Fish or seaweed fertiliser is ideal.

Shallow Roots

Rhododendrons’ root systems are shallow and wide, so don’t use a hoe near the plant. Also, the roots of perennial weeds can get tangled up with your plant. Weed by hand and with care, as you could rip up some of your plant’s roots along with the weed, stunting its growth.

Mandy at PrimroseMandy Watson is a freelance journalist who runs www.mandycanudigit.com.

A plantaholic with roots firmly planted in working-class NE England, she aims to make gardening more accessible to the often excluded – the less able, the hard-up or beginners.

Advocate of gardening for better mental health.

See all of Mandy’s posts.

Mandy, Planting, Plants

Growing soft fruit is very cost-effective, as they’re usually the most expensive crops in the supermarket and are suitable for most small gardens and even containers, as they take up little room.

What do we mean by soft fruit? Well, think blueberries, raspberries, blackberries (and their hybrids like loganberries and tayberries), gooseberries and currants.

Soft fruit does best in well-drained, loamy soil. Before planting, dig over the patch to loosen the texture and add well-rotted manure or granular fertiliser.

Here’s how to plant and recommended planting distances:

Blueberries

If planted in a fruit bed, the soil must be lime-free, as they thrive on acid soils. If your soil is alkaline, try growing in a pot. Plant in a hole that is just deeper than the root ball. Firm in and water thoroughly.

Planting distance: 1m apart in full sun/partial shade.

Suitable for pots: At least 30cm in diameter for young plants, in ericaceous compost.

Best time to plant: Blueberries dislike being disturbed during the growing period, so late autumn or winter when they are dormant.

Raspberries

These much-loved berries are cane fruit and have summer or autumn fruiting, plus long cane varieties.

Canes need to be planted 1cm deeper than they were at the nursery – you’ll be able to see the soil mark. Plant in deep, rich well-drained, slightly acidic but moisture retentive soil in a sunny or partially shaded position. Avoid a windy site. Cut back canes to 5cm above soil level after planting. Keep well watered and top dress with a balanced fertiliser in spring. Do not hoe to remove weeds, as this can slice through growing shoots.

Long cane plants should not be cut back after planting, as they develop fruit-bearing side shoots at the top of each cane. In subsequent seasons, treat as regular canes.

Suitable for pots: Plant single canes in a 38cm container with canes for support in 80% multipurpose compost, 20% loam-based.

Planting distance: Space canes 40-45cm apart and allow 1.25-2m between rows of summer-fruiting varieties and at least 2m between rows of autumn-fruiting types.

Best time to plant: Between November and March, when plants are dormant.

Blackberries (and Hybrid Berries)

Blackberries are not the impenetrable brambles of old – many varieties are thornless with pretty flowers and autumn colour, so are ideal for use in an ornamental garden. They are also parents, along with raspberries, of many hybrid berries, such as  boysenberries, loganberries, tayberries, etc, most of which are treated the same as blackberries.

They’re very easy to grow and unfussy – plant in well-drained but moisture-retentive soil in full sun or partial shade. Cover the rootball with 8cm soil and incorporate plenty of well-rotted manure or compost. Provide support with wires up walls and fences. Cut back to a healthy bud after planting to promote fresh growth.

Suitable for pots: Choose compact, thornless varieties, at least 42cm wide.

Planting distance: Space 2-4m apart, depending on variety.

Best time to plant: Winter-spring.

Gooseberries and Currants

Blackcurrants, redcurrants, whitecurrants and gooseberries are particularly rewarding to grow as they’re so expensive to grow commercially, being very difficult to pick on a large scale. For all varieties, avoid planting anywhere susceptible to late spring frosts and enrich soil with well-rotted manure or compost and a spring top-dressing of Growmore.

Currants like a moisture-retentive soil in an open position in full sun or partial shade. After planting, cut blackcurrants down to 8-10cm above ground level and prune the stems of red and white currants and back by about half.

Gooseberries prefer a deep, well-drained but moisture-retentive soil in full sun or light shade.  Shallow soil will result in poor-sized fruit. Cut stems back by about half after planting.

Planting distance: Space currant bushes 1-1.25m apart, gooseberries 1.25m apart.

Suitable for containers:Yes but repot regularly and top-dress with new soil each spring – avoid spiny gooseberry cultivars.

Best time to plant: November-March.

Mandy at PrimroseMandy Watson is a freelance journalist who runs www.mandycanudigit.com.

A plantaholic with roots firmly planted in working-class NE England, she aims to make gardening more accessible to the often excluded – the less able, the hard-up or beginners.

Advocate of gardening for better mental health.

See all of Mandy’s posts.

How To, Jorge, Planting, Plants, Trees

Adequate spacing between trees is essential for preventing disease spread and ensuring adequate light levels. Below, we have infographics of many common rootstocks, spaced as closely together as possible. However, you may want to alter your calculations based on such variables as:

  • Variety: vigorous varieties (triploids such as Bramley) produce bigger trees and weak-growing varieties (many cider apples) produce smaller trees. +10% and -10% respectively.
  • Environment
    • Soil: nutrient levels, organisms, pH, texture and structure all affect the eventual size of your tree.
      • Nutrients: trees require three main nutrients: nitrogen (N), phosphorus (P) and potassium (K), known as NPK. Deficiencies in any will reduce growth. To address this use organic slow release fertiliser and apply mulch.
      • Organisms: soil organisms play a key role in the soil, transforming nutrients into soluble forms, available for uptake by plants. Organism abundance can be promoted by using organic fertiliser and compost, and by forgoing inorganic fertilisers and compaction.
      • pH: every species is suited to a specific pH range. pH’s beyond the range will render nutrients unavailable for uptake by plants.
      • Texture/Structure: Soil is a mix of broken down rock and organic matter. There are different sized rock particles known as sand, silt and clay with sand being the largest and clay the smallest. The size of the particles affect the drainage properties with the sand draining quickly and clay slowly. Texture is determined by the mix of particles in the soil, producing sand, silt, clay and loam soils. All soils require the application of organic matter to improve their structure, producing the perfect mix of micro and macropores, ensuring water doesn’t drain too quickly or too slowly.
    • Exposure: trees exposed to high winds will grow thicker stems to prevent uprooting. Planting in a sheltered spot is recommended.
    • Sunlight: fruit trees should always be planted in full sun.  If a tree or building blocks out light, you can expect smaller fruits.
  • Row Spacing: it is common to leave spaces between rows to allow easy access to trees.
  • Pollination Partners: it is common for apple orchards to have a crabapple planted as every 6th or 7th tree, planted equidistance. Crabapples can be trained into a narrow pillar shape as all you are interested in is the blossom. Try ‘Evereste’ as an excellent disease resistant pollinator.

Very Dwarfing Rootstocks

It is worth noting that the M27 produces very spindly stems and branches.  It requires permanent staking as it is liable to uprooting. If you are interested in aesthetics, choose a semi-vigorous rootstock.

m27 rootstock spacing

Dwarfing Rootstocks

M9 is the standard cultivar for high-density orchards and is less vulnerable than the M27.

m9_rootstock_spacing

Semi-Dwarfing Rootstocks

Our nurserymen recommend the M26 as the best rootstock for the average garden soil.

m26_rootstock_spacing

Semi-Vigorous Rootstocks

The first free-standing trees that do not need a staking. Trees at this size, may be trained into bushes or standards. Although, it is important to note that the higher the branching starts, the greater the spacing required. It is worth noting that semi-vigorous is bit of a misnomer. Semi-vigorous trees still exert a dwarfing effect, producing a significantly smaller tree than one grown on its own roots.

mm106_rootstock_spacing

Larger Semi-Vigorous Rootstocks

colt_rootstock_spacing

Vigorous (Standard) Rootstocks

Standard refers to a tree grown on its own roots. These rootstocks are the closest you’ll get to a tree grown on its own roots in the wild.

standard_tree_rootstock_spacing

It is worth noting that you can fit more trees in a space if you switch to a high-density orchard system. Such systems can fit hundreds of trees per acre, but require expert knowledge to set up and maintain.

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.

How To, Jorge, Planting, Plants, Trees

planting and caring for apple trees

Autumn is the best time to plant trees as this will allow time for your tree to establish its root system in preparation for next summer’s heat. Whenever a tree is uprooted, it loses most of its root hairs from which a tree absorbs much of its water and nutrients. These hairs will begin to regenerate upon planting, but it takes time. Transplant shock is a result of a tree’s water and nutrient absorbing capacity decreasing suddenly. To minimise transplant shock, it is important to regularly water your tree thoroughly, especially in the few weeks after planting.

Spacing should be based on a tree’s rootstock, which controls how large a tree ends up. This ensures there is adequate light levels and air flows, which prevents disease spread.

  • Apples: M27, M26 and MM106 should be spaced 1.2m, 3m and 3.5-4m apart respectively.
  • Cherries: Gisela 5 should be spaced 3-3.5m apart and Colt 4.5-5m apart.
  • Pears: Quince  C and Quince Eline  should be spaced 2.5-3m apart and Quince A spaced 3.5-4.5m apart.
  • Plums: Pixy and VVA-1 should be spaced 3-3.5m apart and St. Julien A and Wavit 3.5-4.5m apart.

Planting In The Ground

Before planting your tree remove any plants in the circumference of your tree’s canopy as they will compete for nutrients and water. Dig a hole no more than an inch deeper than your rootball. With bare root trees ensure the graft point is above the ground.

Digging a hole with a larger circumference will allow you to improve the horizontal layers from which a tree gathers most of its nutrients. A mix of compost and soil will produce superior drainage/retention properties. Fertiliser will improve the soil’s nutrient profile and mycorrhizal fungi will ensure your tree can gather these nutrients.

A larger hole will allow you to plant a stake, which is essential for any tree with a M9/M26/M27/Pixy/VVA-1/Gisela 5/Quince C/Quince Eline/Quince A rootstock as the roots are too brittle. The stake should be in pointing away from the prevailing wind, so as the tree will not rub against the stake, and no more than 2-3 inches away from the stem.

Scrumptious on an MM106 (left) and M27. Note the difference in foliage and stem thickness.

Water the root ball of your tree and free up any roots with your hands to ensure they aren’t growing in unnatural directions. Potted trees will sometimes have roots growing around the circumference of the pot.

With bare root soak the roots in a bucket of water. 30 minutes to 2 hours is common. Remember to not leave for too long as the tree needs oxygen too. Pruning woody roots back a few inches will stimulate the growth of more fibrous roots on which most root hairs reside.

Place the tree as so the graft is above ground level. Fill up any gaps with your potting mix, but do not compress the soil! Compaction will make it more difficult for water and air to reach your plant’s roots. The soil may reduce over time, so check up on your tree and add additional soil if necessary.

Give your tree a good watering and water bimonthly for the next two months. Adding mulch is recommended as it will improve the soil’s moisture retention. You can use bark and wood chipping, compost, manure, leaf-mould and stones, but be sure not to use infected materials. Make sure the mulch doesn’t touch the stem or it may transfer disease.

Mulch will help your tree retain moisture.

Tie your stake to the tree. Primrose recommends using a rubber tie that can be adjusted as your tree grows and nailed to the stake. Be sure to double knot your tie to prevent it from slipping. Placing a rabbit guard around the base of your tree is recommended as hungry rabbits nibble on bark come winter.

With bare root trees, cutting back the branches will produce a better balance between the root system and top growth, prevent the tree rocking in the wind and produce more fruit buds. Cut the central stem back by a third and the branches by half, snipping right above the buds.

Planting In Pots

With containers insufficient nutrient and moisture levels necessitates frequent watering in drought, biennial partial replacement of the soil and use of mulch. Using a potting mix of compost and garden soil will produce soil with the best drainage/moisture retention properties. Adding fertiliser is recommended to boost nutrient levels. When watering insure you give the pot a good drenching, this will ensure the roots grow to the extremities of the pot.

  • Apples: 40-60 litre containers (35-40cm2 planters) is the minimum volume for a M27 tree. Choosing a tree with a M27/M26 rootstock is wise. M27 rootstock produces the smallest trees, but M26 copes best with underwatering. 140L containers are recommended for more vigorous rootstocks.
  • Cherries: Gisela 5 and Colt can both be used, although Gisela 5 is recommended for smaller containers.
  • Plums: success has been reported with both Pixy and St. Julien A, although it is recommended to use Pixy with smaller containers.

Care

Adding fertiliser in spring will help your tree grow once it comes out of dormancy. Replacing any decomposed mulch is worthwhile. Check your ties to ensure there is no unnecessary rubbing. Come autumn, collect and compost fallen leaves to remove potential vectors of disease.

Pruning is key to establishing an excellent framework. Trees need to be bottom heavy with larger branches at the bottom than at the top. The central leader (main stem) should be higher than any scaffold branches (branches growing from the main stem) and competing branches should be removed. Scaffold branches will often grow vertically, but need to be weighed down when young, so they grow horizontally. Scaffold branches growing too close together are best removed. Keep horizontal branches growing off scaffold branches (secondary scaffolds), and remove vertical ones. Remove diseased, weak and twiggy growth and periodically thin to allow light to penetrate both the interior and lower portions of the tree.

Jorge at PrimroseJorge works in the Primrose marketing team. He is an avid reader, although struggles to stick to one topic!

His ideal afternoon would involve a long walk, before settling down for scones.

Jorge is a journeyman gardener with experience in growing crops.

See all of Jorge’s posts.