Say the words “Lollipop tree” to any child and it’s likely to conjure up Enid Blyton-esque images of stiff branches magically laden with delectably sugary confectionery. My own inner child wishes that such a tree existed, if only for the fun that taxonomists would have in naming it: Lolius arboreus subspecies deliciosa has such a nice ring to it, don’t you think?

The truth, however, is a little more prosaic, and so the term “lollipop tree” refers to a form of topiary where the plant has been carefully trained or pruned to create a perfect sphere of foliage growing atop a tall, single bare stem, so that it ends up looking just like, yes, a lollipop.

Take a stroll through any of Dublin’s leafier suburbs (or indeed, most other European cities) and you’ll see numerous examples of container-grown lollipop trees, properly known as “standards”, being used to frame doorways or entrances. The majority are topiaried specimens of culinary bay (Laurus nobilis), an evergreen Mediterranean species with glossy foliage, but other evergreen species are sometimes used including holly (IIex), Portuguese laurel (Prunus lusitanica) and Photinia. What you’ll also almost certainly notice, if you give these lollipop trees a second, closer glance, is how utterly woebegone so many of them look, their foliage sparse and yellowing, their branches brittle and uneven.

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Remedial problem

If this all sounds all too painfully familiar, then you’ll be relieved to know that the problem with your lollipop tree – a simple, easily remediable one – is that it’s pot bound. This is not at all unusual: confine any plant to a container of compost for long enough, and inevitably it will start to show signs of nutrient deficiency as well as stress brought on by a decreasing ability to tolerate periods of drought or temperature extremes. It’s like a human trying to survive on watery gruel: after a while, the fight for basic nutrients begins to show.

The only way to restore your lollipop tree to its leafy best is to re-pot it, a job best carried out at this time of year as the plant starts back into growth. It’s a simple, if slightly messy task that can easily be completed over the course of an afternoon, ideally as a two-person job.

Before you start, you’ll need to buy a bag or two of good-quality, soil-based compost such as John Innes No. 2/ No. 3, which has the advantage of being heavier (thus making the container less likely to blow over) and more moisture retentive. You’ll also need a good-quality, slow-release granular fertiliser.

To contain the mess, use a sharp scissors to cut the seams of a black refuse sack apart, and spread this out like a tarpaulin on the ground. Then take your lollipop tree and gently pull the plant away from the pot. If it’s very badly pot bound, or if it’s growing in a narrow-necked container, this may be difficult. In this case, lay the pot gently on its side and tap the base and sides to loosen the roots, while gently rocking the plant by the base of its trunk (this is where the two-person part of the job comes in).

Once you’ve succeeded in removing the tree from its container, you need to gently loosen the outer layer of old compost from around the root ball. If the root system looks very badly congested, consider planting the tree into a larger container or out into the garden. Otherwise, use a secateurs to cut away a little of the plant’s outer layer of thin, fibrous roots. Then place a layer of compost, enriched with a handful of the slow release granular fertiliser, in the bottom of the container and re-pot the tree, making sure to replant it to the same depth, leaving at least an inch between the top of the compost and the rim of the pot. Place more compost, enriched with another handful of slow-release fertiliser, gently firming it down in and around the edges of the root ball until it reaches the same height. Finish off with a good watering.

To keep your container-grown lollipop tree hale and hearty, grow it in a place where it’s sheltered from strong winds and extremes of temperatures. During the growing season, keep it regularly watered, but avoid overwatering as this can stress the tree’s root system. Either an occasional top dressing (every four to six months) with a slow release fertiliser or regular liquid feeds will help maintain vigour.

Keeping your tree in good shape is another matter – you’ll need to trim it quite regularly. Recommended pruning times and frequency vary according to the species; culinary bay and Photinia, for example, should be pruned once a year in late spring/early summer, holly in mid to late summer, and the fast growing Prunus lusitanica two or three times a year (February, June and then again in October). The result will be a tree you can be proud of. Sadly, it still won’t produce lollipops, but you can’t have everything.

This week in the garden

Slug patrol If you're growing plants from seed this spring in a glasshouse, polytunnel or under cloches, it's crucial to keep an eagle eye out for slugs, which can decimate emerging seedlings overnight. Make it a daily habit to examine the base of each seed tray, one of their favourite hiding spots. If you find any slugs, slice them in half with a scissors or sharp secateurs.

Prune roses Finish pruning roses before sprinkling some slow-release fertiliser around the base of each plant and finishing off with a mulch of garden compost or manure. If possible, use an organic brand of fertiliser, such as OSMO Organic Rose Feed, available from White's Agri (€4.95, see whitesagri.ie)

Seed spuds Plant potatoes (see last week's column), making sure to give them a free-draining soil in full sun, enriched with plenty of organic matter. Early varieties such as 'Casablanca', 'Queens' or 'Orla' should be planted 25-30cm apart with 45-50cm between rows and will typically be ready to harvest within 12-14 weeks of planting. Maincrop varieties including the blight-resistant Sarpo 'Mira', 'Bionica' and 'Tibet' should be planted 40cm apart, with 75cm between rows. These can take up to 22-24 weeks to be ready to harvest.

Dates for your diary

Thursday 24th March, 8pm: National Botanic Gardens, Glasnevin. The Stans: Plant Exploring in Afghanistan, Uzbekistan, Tajikistan and Kyrgyzstan, a lecture by John Mitchell on behalf of the Alpine Garden Society (Dublin Group)

Thursday, March 24th-Saturday, April 3rd: The annual Kiltrea Bridge Pottery sale, Enniscorthy, Co Wexford, includes lots of garden pots and rhubarb forcers. kiltreapottery.com