Gardeners’ Blog – April 2018

April is turning out to be a busy month around the gardens with the Easter events, followed by the annual tree surgeon’s visit, evaluating the health of the trees within our collection. Most of the work is carried out for safety reasons, to make sure that the trees are in good shape and are healthy. This also presents us with a new planting opportunity, allowing us to constantly improve the diversity of our collection.


What’s more, we’re really excited to watch as our newly planted herbaceous border wakes up from its winter slumber, with temporary hazel structures coppiced from our nature reserve helping to support the tallest subjects. We will also be continuing with lawn repairs and involving students from BMET College as much as possible with some of our seasonal jobs. Last month, three groups helped to prune the roses in the rose garden, which meant that the job was finished faster and more efficiently.


We’ve been clearing out overgrown areas on our woodland walk, replanting it with plants from North America and broadening the variety of plants we have on site, so keep an eye out on your next visit.


In April, the gardens will be a riot of colour – around every turn there will be plants providing valuable nectar for insects. From the middle of April, the Magnolias will be looking stunning and are a sight to behold in the Rock Garden (fingers crossed we don’t have any late frosts that will damage the flowers).

 Magnolia Stellata 

Meanwhile, jobs in the nursery during April include: staking pots of elegant, flame-like, lily-flowered tulips, which were planted in October and kept in a dark cold frame for the winter. With the warmer weather hopefully here to stay, we will now place them in the Mediterranean House display, along with, Pericallis Senetti™ and Schizanthus. Schizanthus are commonly known as ‘poor man’s orchids’ as the multi-coloured flowers resemble miniature orchids, but can be grown from seed at a fraction of the price.

Gardeners' Blog - April 2018

The work doesn’t stop there, we’ll also be potting 3,500 bedding plug plants into cells and growing them in the Nursery, before planting them out in late May once the risk of frost has passed. Make sure you visit the bandstand, Loudon Terrace and the Front Entrance on the car park to see these vibrant specimens during the summer.


We’ll also be looking to replace the Pelargoniums in the Mediterranean House, commonly referred to as ‘geraniums’, with young plants, which were propagated from cuttings last September. These too will flower all summer long and, with luck, throughout next autumn and winter too!


If you have read our previous blogs, you’ll also know that we have been working on our interpretation labels. We’re delighted that all 200 educational plants within the glasshouses have now got brand new labels. Plants such as tea, coffee, cotton, bananas, Aloe vera and many more are clearly described with up-to-date facts and findings according to APGIV (Angiosperm Phylogeny Group classification 4), the latest in plant nomenclature (naming) since 2016.


Last, but certainly not least, now that it is warm enough, we will be releasing our first biological control of the year into the glasshouses for pest control. ‘Biological control’ refers to using various beneficial insects to prey on others that cause plant damage. Encarsia is a tiny parasitic black wasp that controls whitefly, Cryptolaemus, a dark brown Australian ladybird controls mealybug and a Bacillus bacteria will be used to control tortrix moth caterpillar. All of these are completely harmless to humans and have been used in the horticultural industry for decades.

Justicia Carnea- April Gardening Tips

As you can tell, April is a great time to get out in your garden, and there is so much you can do. You could:


  • Finish sowing tomato seeds indoors ready to plant out. If you’re struggling for growing space, buy ready-grown tomato plants and grow them on
  • Continue to sow all hardy and tender seeds under cover – take care not to expose them to frost
  • Keep an eye on your seedlings. As soon as they have their first ‘true’ or adult leaves (the pair after the cotyledons or ‘seed leaves’) put them in pots or modules of their own
  • If your greenhouse is heated, plant your summer hanging baskets with plug plants and keep them under cover until all risk of frost has passed
  • Pinch out the tips of fuchsia shoots and sweet pea plants to encourage bushy plants this summer
  • Dust the mower off and make sure you use a higher cutting setting to prevent shocking or damaging the lawn. By only removing a small portion, this will encourage the grass to produce strong new growth
  • Now the soil is warming up, sow hardy annuals in finely cultivated soil
  • Keep on top of weeding and prevent them flowering and going to seed
  • Start to apply slow release fertiliser around beds and borders