Window box advice for long lasting colour

[Batinahat]

Hoping for some advice regarding a window box I have. In January I planted some lovely large tulips which have now finished flowering and my window box is empty again. I am wondering a few things:

• what should I plant next to give colour and ideally flower for a nice long time?
• can I plant on top/around the tulip bulbs? Assuming if I leave the tulip bulbs in there they will flower again next year? Is this right?!
• will I need to plant something new again later in the year to give year round colour?

Geraniums are very hardy for window boxes.

It’s a bit early to plant bedding plants out, best to wait until the danger of frost has passed. You will have to remove the spent bulbs and store then in a dark, dry place for next year. Or plant them in the garden.
Replace some of the compost with fres and plant food, then plant trailing lobelia, geraniums, and bedding Begonias they will give a lovely display.
To give an all year round structure, I’ve often put very small, slow growing firs in my window boxes. They last for a couple of years before growing too large. You can usually buy them in groups of four at garden centres.

The trick with good looking window boxes is usually to hedge your bets with a variety of different plants, so that something is always looking good, colourful and drawing your eye away from the ones that are struggling or past their best.
Visit a local garden centre or nursery, and try a variety of different plants over a year or two; see what does well in your location and what doesn’t. If you end up with an unsightly gap, you can usually pick up a little pot of something in its prime for around £1 and plug the gap. I redo my boxes completely twice a year in May and Sep / Oct to keep things looking tidy but do plug gaps in this way throughout the year - I rely a lot on ready-grown miniature daffodils and primulas at this end-of-winter time of year! When something has finished, I will often pull it out and replace it.
First the tulips. Cut the dead flower heads off and leave the leaves for at least 6 weeks to die back naturally - essential if you want the bulbs to reflower next year. This does not make large bulbs ideal for a window box as the foliage will look messy for a while to come. Worth considering in future. Small bulbs with finer foliage eg grape hyacinths and “tete-a-tete” miniature daffs are usually less dominating and it is easier to hide the dying foliage. You might want to consider removing the bulbs, and let them wither and die away from the window box, to replant in the autumn.
You will probably be able to pick up some pansies now which will do well through spring and into early summer. Geraniums are much the easiest to manage from May onwards (it’s too cold outside for them at the moment - assuming you’re in the UK?) as they flower all summer, are forgiving if they dry out and are easy to deadhead (essential for most / all plants to prolong the flowering time).
A lot of people use petunias which flower for ages if you keep watering and keep deadheading. It’s nice to add something that trails, and something slightly taller to give the box structure.
The key to a successful summer box is WATER REGULARLY; every night if it’s hot, and at least three times a week in “normal” weather. Even if it rains, don’t assume they will catch much water - water anyway. I use a feed called Miracle Gro once a week or so, which you can buy in any garden centre or some supermarkets.
In the winter, most plants will struggle a bit.... people tend to plant winter pansies, cyclamen or heathers (I never have much success with the latter - don’t think they like my aspect / soil) which are somewhat frost resistant. Not a bad idea to include a miniature conifer and / or some trailing ivy to give the box some colour / structure even if the other plants are looking a bit sad. They won’t need so much water; once a week will be fine, and in fact they won’t like getting waterlogged.
Sorry for the essay but hope it helps. I don’t have much front garden so my window boxes really brighten my aspect and I feel it’s worth throwing a bit of money and effort at them as they make me smile year round. Much better value than a bunch of cut flowers. It’s just a matter of experimenting to see what works best for you and your location.
NB all of the plants I mention are really basic... if you don’t know what they are, google and you will immediately recognise them. You will be able to pick them up anywhere that sells plants.
Good luck!

JT05 this is probably the most comprehensive article I've read on window boxes anywhere! I started doing mine a 18 months ago and have done a lot of googling for advice and you've more or less summarised everything I've learned in one post. Mild crush on you right now

Wow, thanks everyone so much for the advice, I have learned loads on the last 10 mins reading these!

@Theanxiousgardener you have given me a complete beginners lesson in window boxes, thank you so much!

So, I am thinking that I might remove the tulip bulbs and as some suggested consider planting these in my garden rather than back in window box next year and consider smaller leaved early spring offerings next time. I did love the bold impact of the tulips when they flowered but the leaves are massive and now the flowers have gone it's all a bit sad waiting for leaves to die!

I have an aversion to geraniums but everything else mentioned I googled and like so will definitely look to include a mixture of things from May onwards. I actually do have some trailing ivy in the box already so seems I instinctively got something right! Last year I spent ages planting the box with some lovely little violets/violas?! (Yellow and purple little flowers) and it looked great for a week and then there was a heatwave and everything dried up and died despite what I thought was enough watering (clearly not!).

Armed with all of your tips I feel brave enough to try again...I do also feel pleased the tulips I planted flowered and didn't die early so feel I am progressing if slowly and learning something.

To answer a couple of questions, yes I am in the UK, in the East (Anglia) so usually dry (ignoring this very wet year!) and warmish. Window box is on side of house that faces south but due to various things casting shade is part sun/part shade. Love bold shapes and colours especially yellows, blues and purples and height/impact.

Thanks all so much you have really spurred me on! 😀

The other thing I would suggest is look out for other successful window boxes - especially those in your area, or with a similar aspect. Analyse what it is that you like - colours, structure, plants? And bookmark those ideas in your head for future use.