Commonly called Mock Orange, Philadelphus are heavily scented flowers reminiscent of the true orange blossom of the Mediterranean region. It begins to produce its scent in the garden as soon as the first flowers open, continuing until the shrub is covered in bloom with a showstopping fragrance from the beginning of June through July.

All Philadelphus are deciduous shrubs, grown for scent but also useful for bringing structure and interest to the garden. There has always been debate on whether single flowered Philadelphus are more fragrant than double flowered ones. The jury is out, but I am inclined to think that the single flowered ones have the best scent.

Philadelphus ‘Minnesota Snowflake’ is a large grower attaining heights of 2.5m and is reliable for flowering performance. It commands attention creating a spectacle when in flower and abounds in scent. It has pure white double flowers. P. ‘Sybille’ forms a compact shrub to 1.5m with arching branches and quality foliage. It earns its place in any garden. The single flowers have a dark purple eye, which is a feature of other cultivars.

Philadelphus x lemoinei is over 120 years old and still holds its valued place in gardens. It is said to be the one with the most powerful scent, growing to 1.2m. I’ve seen specimens of over 3m high, so it is a great space filler, if that is what is required.

P. coronarius ‘Aureus’ brings with it the scent we expect, but with golden yellow foliage, which adds an extra dimension to the group. It is a large shrub getting to 2m in height with creamy white scented flowers appearing in late May. It makes a beautiful colour combination with purple berberis, so it extends the season of interest in the borders.

Recently available in the nursery trade is Philadelphus ‘Petite Perfume Pink’ which provides the gardener with little space, the opportunity to appreciate the scent and beauty of Philadelphus.

Plant breeder

Bred by Alan Postill, an English plant breeder, who made it his mission to produce a pink-flowered Philadelphus – and this is it. The flowers are delicate pink with a richer pink centre. He went one step further and produced P. ’Petite Perfume White’ which is pure white with all the same qualities. Both of these have an extended flowering season beginning in May through July. They grow to 1.5m, perfect in a large container on your patio or yard.

Philadelphus with double flowers are hard to beat. They have a full cluster of petals, which partly or fully hide the centre of the flower. Philadelphus ‘Boule d’Argent’ is a beautiful sight with its arching stems carrying pure white double flowers with yellow stamens, highlighting the centre of the flower. It is a vigorous grower to over 1.5m in height with pearls of pure white scented flowers, a memorable sight. P. ‘Snowbelle’ grows to 1.5m in height with fully double flowers, almost like pompoms. Although it has great beauty, reports say it is not the most fragrant. However, I would still suggest growing it for the quality of the flower.

Philadelphus ‘Manteau d’Hermine’ is smaller in stature, growing to just over 1m and flowering a little earlier than others. It produces clear white little balls of flower with wonderful scent. P. ‘Pearls of Perfume’ is a recent American introduction now available on the market. Its pure white double flowers remind me of mini powder puffs and are beautifully scented too. It is a compact grower to 1.2 m high and a little less as wide.

Cultivation: Like all plants, but particularly with shrubs which are going to be in your garden for many years, soil preparation is key. Prepare the soil well by digging in well-rotted farmyard manure or good quality homemade compost. Choose the site carefully, taking into consideration its eventual height and width.

There is nothing worse than having to continuously heavily prune shrubs to fit within your available garden space. Philadelphus flower well on growth produced the previous year so it is important to encourage new growth on a yearly basis. The key is to watch which shoots are flowering, and in their midst, you will see fresh growth making its way through and these are the shoots that will flower next year.

Once flowering is over, cut back all flowering shoots to ground level making way for new growth that is going to bloom for you next year.

I have notches on my rose leaves, the size of a 10-cent coin. What is causing this and what can I spray to prevent it? – Mary, Co Waterford.

This is the work of the leaf cutter bee which is active at the moment. The bee is using the sections of leaf to build a nest in which to lay her eggs. She cuts a clean notch from the edge of the leaf and flies with it suspended between her legs. Then she forms the pieces of leaves into small nests in which she lays an egg. After this, she then seals the nest and creates some more. These are solitary bees and build their nests in hollow stems or decaying wood.

They are excellent pollinators, so I don’t recommend you spray in this instance and let them go about their business. While there is damage to the foliage, it is not injurious to the plant.

Roses:keep an eye on roses and make sure to remove all spent flowers. This will extend their flowering period. Look out for outbreaks of Black Spot. Remove any damaged leaves and never allow infected leaves to lie on the ground.

Trees and shrubs:all new plantings must be watched as dry periods will delay establishment. Examine flowering cherries for wayward branches and lightly prune to retain shape.

Indoor plants: house plants can be stood outside now and repotted, if needed. Observe watering carefully as they may require more.