What can be planted with Forsythia

caroall

I am just about to plant some Forsythia Lynwood to help disguise my neighbour’s horrible “homemade” garage and to have a bit of colour in the Spring.  I have dug in some compost. Is 1m apart enough?  I would also like to have some other plants for Winter and Summer to give some colour – I was thinking of some heather which seems to grow well in my garden.  Not sure what else would grow.  It is an East facing wall with plenty of sun.  I am in the Chilterns so there is a lot of chalk in the soil. Thanks for your help.

Fairygirl

Make sure you pick the right Heathers. It's Ericas you need as they'll be ok in chalkier soil because it's usually more alkaline. They're less fussy than the Callunas, for example, which need more acidic soil. There are hundreds of different types, but generally speaking, the ones which flower winter into spring cope better with a bit of alkaline soil.
I'd say your Forsythias are too close together. They get big, so you'd need to keep pruning them
 
What room have you got for other plants though? Is it perennials or shrubs you want?
A photo of the space would help 

caroall

Thanks Fairygirl.  I haven't planted the forsythia yet.  I'll nip outside and take a photo and post later

Fairygirl

No probs. It just helps to know what room you have. No point in us suggesting loads of big shrubs or perennials  if you only a few square feet to play with!

caroall

Pic just taken attached - ignore the tree and house shadow. Border can be widened to 1 metre.  Cotoneaster franchetti on right hand side.  

Fairygirl

The Forsythias will take up a fair bit of the space once they're mature. Are you going to put one at each end - roughly?
That would give you a central space which could either accommodate a shrub which would flower later, and/or a climber - loads of clematis will suit that spot. Weigelas would be fine in that aspect, Spireas and Potentillas too.
The space in front could have some of the heathers you mentioned earlier, but if you want more variety for later in the year, you can have other perennials - hardy geraniums are very easy and there are loads to choose from. Readily available too. Spring bulbs are always good to add in at the same time to extend the season.
Others like Lychnis, Lilies and Liatris would give you verticals which wouldn't take up a huge amount of width/depth. Astrantias and Asters would give colour through until autumn, and so would Crocosmia and Heleniums if you like brighter colours - they're mostly red/oranges/yellows.
Other posters will have suggestions too. 

caroall

Thanks for your suggestions. I was thinking about planting 3 equally along the space (it’s just over 7 foot and keeping them well pruned so they grow upwards) with planting between them and in front of them. Clematis sounds like a good idea but I presume I would need to have something for it to climb to.  I like the idea of Lynchnis and Liatris as I really want vertical rather than width.  I have some dahlia tubers I dug up (can I split them before replanting?) and some hardy geraniums I split in the Autumn some of which I could put there. 

Fairygirl

The clematis will scramble through the Forsythias, especially if you want three, although I think that's one too many. If there was only two, you could put some trellis in the centre, against that inner wall [ I assume that's yours though?] fixed to posts, which would be a feature in itself in winter, and would carry part of the clematis. It would depend on the type you chose too, as to the flowering time, but a viticella one would probably be best, as they flower in summer onwards. It could be a problem in future though, if you want to keep pruning those forsythias.
Do you mean the border is only 7 feet? It looks much longer than that. One forsythia would probably fill a 7 foot length. 

The dahlias would need to be mature enough for splitting, so a photo would help with that. Each piece needs to be viable, with a growing point. They need plenty of sun, food and moisture, so there may not be enough there once the forsythias mature. They might be fine for a few years until that happens.   

caroall

The part of the border which needs to be planted is just over 7ft.  I hadn't considered using the forsythia as a climbing frame frame for the clematis so will actively look at that - thinking about a blue/purple one maybe clematis multi blue.  The wall isn't ours so cant fix anything to it.  Take your point about the dahlias so will put them back in the border they came from. Need to do a bit more work on that border once the dahlias are in place.

Fairygirl

The natural growth habit of clematis is to scramble through other shrubs/trees. It's only because we tend to use them on fences or walls etc, so that we see them more clearly, and also so that they can be used as a backdrop to other planting. 
The choice will be the main factor, because of pruning - of both the Forsythia and the clematis. If you didn't need to prune the Forsythia, one of the early ones would be fine, but that puts paid to the seasonal interest.
Most forsythia pruning gets done after flowering, and normally wouldn't need done every year, and a Group 3 clem would be pruned just before that -late winter/early spring. It would generally be easy enough to do that. 
Group2 clems wouldn't work quite so well, as they flower in spring and also later on, and don't need annual pruning, but if you were pruning the shrub, you'd probably end up chopping off some of the clematis. That would delay the spring flowering [not a major problem as such] but would lose later flowers. Again, it might only be every so often that the forsythia would need pruning, so it may not be a huge problem. 

If you only have 7 feet of border, you wouldn't need 3 forsythias. That density of planting would only be for hedging. 

JennyJ

I have a Forsythia (probably suspensa judging by the growth habit) in front of a fence, in a kind of flat fan shape. It's currently about 8 feet wide at the widest point (one fence panel plus a bit of the two each side) but would be wider (RHS says 2.5 to 4 metres) if left to its own devices. I take out a few of the oldest, longest branches down close to the base every year after flowering. I think Lynwood is more upright and less arching, it's spread is apparently 1.5 to 2.5 metres, so one or at most two would be plenty for the space. In my view, forsythia is best not clipped at the sides when they get big to keep them within a narrower space than they want - that "bog brush" look - but if that's what you like then then it's OK, there's no Forsythia police .