Primula and proper! The most satisfying way to grow lovely primulas is from scratch, with seed, says Monty Don – and now’s the right time to do it

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Now is an excellent time to create more primulas for next year by lifting and dividing them. 

The perfect moment to do this is just after flowering. Dig up a patch or a large clump and carefully tease it apart so you have a number of little plants, each with their own roots and crown. 

These can then be planted out either individually or in new groups, spacing each of the individual plants about 15cm apart. 

Expert gardener Monty Don said now is an excellent time to create more primulas for next year by lifting and dividing them

Water well and do not let them dry out until they are growing strongly. Ideally every clump should be divided at least every three years to keep the flowering as vigorous as possible.

Primulas are also very easy to grow from seed, which is by far the cheapest method and in many ways the most satisfying, with one packet giving you scores of plants. Now is the ideal time to sow them. 

The seeds should be scattered thinly onto the surface of a peat-free compost and not covered, as they need light to trigger germination.

I always fill a seed tray with compost and then soak that in a sink, let the excess drain and sow the seeds into damp compost. 

If you soak after sowing, you risk spreading the seeds so they end up all around the edge of the tray. 

Ideally you should place a sheet of glass over the seed tray to keep it moist, but failing that, spray it a couple of times a day so the compost never dries out.

Germination will take about three weeks and then the seedlings should be pricked out about 5cm apart or singly into plugs. 

Ask Monty 

Q: Last year every fruit on our two Victoria plum trees had been bitten into. We think it might be wasps – is there a spray that’s safe to use?

Gill Pellagrino, Notts

A: No pesticide is ever safe to spray fruit with. If wasps are the cause, you need to find their nest and perhaps have that dealt with. However, they do a lot of good in the garden, eating caterpillars, so losing a few plums could be worth it.

Gill Pellagrino from Nottingham asked if there is a spray that is safe to use on her Victoria plum trees

Q: Despite spreading lots of home-made compost, my vegetable plot has few worms. My compost bins produce lots of small worms I sometimes put in my veg plots but they soon disappear. Local lawns also seem to have a poor worm presence. How can I fix this?

Jim O’Rourke, Co. Down

A: The worms in your compost heap are a different species from those in your veg plot or lawn. But both dislike acidic soil, so if yours is acidic, you could increase its alkalinity by adding lime.

Jim O’Rourke from Co. Down asked why his compost bins produce lots of small worms

Q: My 60-year-old rose bush has become very woody and leggy. Can I revive it by pruning?

Glenys Vernon, Cheshire

A: If you prune it hard now, cutting back to the lowest visible bud, new shoots will emerge that should bear flowers. But 60 years is a good age for a rose, so expect an improved display –but perhaps not the full vigour of youth!

Glenys Vernon from Cheshire said her 60-year-old rose bush has become very woody and leggy

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Let them grow on through the summer and they will be ready to plant out in autumn.

Most of the many hybrids and varieties of primulas you see for sale in garden centres can trace their parentage back to one of our two native primulas, the primrose, Primula vulgaris, and the cowslip, Primula veris.

A cross between the two is sometimes referred to as the oxlip, but the true oxlip is a separate species and increasingly rare. 

You will, however, often see cowslip-like flowers, on tall stems with primrose-like leaves that are much coarser and more crinkly than a cowslip’s, as a result of the hybridisation from these two parents – and then many further crosses after that. 

The result is often lovely, but seeing the simple plants growing naturally is what gives me most pleasure.

Cowslips like sunshine, and chalk downland is their archetypal habitat, but they are actually quite flexible about their conditions as long as the soil is not too acidic – they thrive in wood meadows, glades and verges.

They are perennials and, given the right circumstances, can live for decades. 

The seeds drop and seedlings emerge very close to the parent plant so they evolve and spread in patches and clusters which, with the help of gravity, will invariably be down any slope.

Primroses, on the other hand, are woodland plants that do best in light, moist shade, ideally at the base of a hedge or on a mossy bank or among shrubs. 

Like cowslips they are pretty adaptable, but the one thing they hate is drying out – those planted around the roots of growing trees soon suffer, as the trees suck up all available moisture.

Primroses are also an excellent source of nectar for bees, bumblebees, butterflies and moths. 

The seeds are spread by ants and mice that are drawn to the oils that coat them. This means the plants will pop up in cracks in paving, around the base of walls or among the roots of shrubs.

MONTY'S PLANT OF THE WEEK

STAR MAGNOLIA (Magnolia stellata) 

This is usually the first magnolia to flower.

It is a woodland shrub, native to Japan, with lovely starbursts of white petals on bare branches. It grows slowly, not more than 3m tall, but the fragrant flowers last for weeks.

It will tolerate alkaline soil if it has plenty of leaf mould or garden compost. ‘Royal Star’ and ‘Water Lily’ are two varieties with extra-large flowers. Those of ‘Rosea’ and ‘Jane Platt’ (pictured) are flushed with pink. M. kobus is very similar but the flowers are born on a more vigorous tree so it should be planted with plenty of space around it.

Monty's plant of the week: Star Magnolia (Magnolia stellata). He said this is usually the first magnolia to flower

THIS WEEK'S JOB: TIDYING BULBS 

Resist temptation to cut or tie back the foliage after bulbs flower. 

You can lift the foliage, bulb and roots from a container and pot them up into an old plastic one, which can be put to one (sunny) side to die back and feed next year’s bulb with no decaying foliage on view.