Protection of Historical Monuments and Climbing Plants

About the monument authorities

There is no question that the climate needs to be protected, including by increasing greenery in our cities. But people not only need a good climate, they also need to ‘anchor’ themselves in order to stay mentally healthy. They need something like a ‘home’. This in turn includes places and buildings that create identity, and this is where heritage conservation comes into play. It ensures that such places are preserved, supported and developed.

By its very nature, this ‘preservation of monuments’ is geared towards very long periods of time, and responding to supposedly short-term sensitivities is alien to it. This is why monument conservation does not want to see solar modules on roofs or greenery on walls (for the time being), no matter how urgent the climate issues may be... In terms of greening, nothing works without the ‘monument conservation’ authority.

But how are these authorities structured? According to experience in Leipzig / Saxony, the will to green always initially comes up against the local, i.e. municipal monument conservator, the ‘Lower Monument Authority’. Depending on their training, employees of the monument conservation authority have an architectural or a more cultural-scientific orientation, usually a clerk is responsible for a certain area or district and ‘manages’ the monuments there. These can be houses, gardens, parks or smaller monuments.

Every few years, there is probably a rotation of responsibilities within the administration, and of course there are also age-related changes in monument personnel. This is important to know because although the local authorities have guiding principles for dealing with their monuments, the individual ‘monument conservator’ sets their own priorities and therefore plays an important role. Depending on the significance of a monument, the opinion of the ‘higher monument authority’ (at the level of the respective federal state) is also sought when deciding in favour of or against greening.

And finally, the monument authorities also have financial leverage to push through requests:

- They can hand out subsidies.

- They can promote tax concessions (depreciation).

- But they can also impose fines.

Germany's oldest façade greening: the 1000-year-old rose on Hildesheim Cathedral / Lower Saxony

Roses, Goethe's garden house in Weimar / Thuringia, historical photography before 1929

Preservation of a Greening

There are monuments that are protected together with their greenery. This is usually the case if the planting took place during the construction period, as is the case with the 1000-year-old rose at Hildesheim Cathedral. The rose is part of the foundation myth there!

But greenery planted later can also be worthy of protection. One example of this is Goethe's garden house in Weimar, which the ‘Privy Councillor’ acquired, remodelled and provided with trellises for roses, vines and honeysuckle. There are records of this, right up to the purchase of the wooden trellis slats around 1776. Since then, the trellises have been maintained almost without interruption as part of the monument and have been immortalised in countless depictions. I wonder if the greenery would still be on the house if a less famous builder had built it back then?

Many historic buildings were subsequently greened in the period around 1900, such as inns and town halls. It is known from Quedlinburg Town Hall in Saxony-Anhalt that greenery with climbing wires and five-lobed wild vine (Parthenocissus quinqefolia “Engelmannii”) was added at that time to bring ‘fresh, good air into the stuffy offices’. And sometimes these plantings have survived to this day, are an inseparable part of the monument and are not questioned.

Restoration of a Greening

Many monuments have lost their greenery over the decades because the plants died, maintenance was too costly or because they were deliberately ‘de-greened’. Sometimes it was a caretaker who neglected his duties, and not so rarely a ‘cost controller’ who saw potential savings and had the greenery removed. Often it is also changes of ownership as well as renovation and remodelling measures that lead to the loss of greenery. However, when times and therefore priorities change, there may be a rethink later and a desire to restore the greenery.

If it is then possible to prove the former greening of a building on the basis of old photos, such as at the University Hospital in Leipzig / Saxony (see photo here), and if the greening was ‘characteristic of the location’ for a long time, the chances of revitalisation are good. However, monument protection authorities are often keen to see a lot of historical trellis and as little greenery as possible. It may be possible to respond to this by choosing suitable plants. But the process can also go the other way round: If the conservation authority wants to see a historic trellis returned, other, easier-to-care-for plants can be planted as an alternative.

So if old photos can be used to prove that a building was previously planted with greenery, possibly even later than the time of construction, and if the greenery characterised the townscape for a long time, the chances of revitalisation are good.

This front building of a former aristocratic residence in Weimar / Thuringia had wooden trellises covering the gable. The trellises remained or were rebuilt, but the much easier-to-care-for thicket creeper was chosen for the planting, as no yield is needed in the museum space.

Thicket creeper (Parthenocissus inserta) on a house in Weimar / Thuringia

Laucha / Unstrut / Saxony-Anhalt: This clematis was bred and planted centuries after the construction of the house. Nevertheless, it seems as if it has always been there...

Adding greenery

Sometimes there are reasons to introduce greenery even to old houses that have never had any planting, if only to breathe new life into the “cold grandeur” of some perfectly restored listed building façades. In such cases, however, the authorities can throw a spanner in the works. After all, as it is a listed building, the view of it must not be obstructed...

Some building owners shy away from this dispute and opt for ‘guerrilla’ greening as a precautionary measure, using plants that have supposedly self-seeded there, potted plants (without holes in the paving), and simple climbing ropes that can be easily removed if necessary, etc.

It can, of course, be a delicate, partial greening scheme, with clematis or annuals. And if a delicate plant then creeps up against a listed building, stands up straight, holds out its little hand imploringly and begs for a thin climbing rope that is almost invisible, hardly anyone will deny it, not even the most hardened conservationist…

But this ‘guerrilla’ greening approach doesn’t always work out! It’s even possible that, within the same city, the heritage authority and the parks department might end up at loggerheads because the climbing plant has now grown to over 3 metres in height and is therefore ‘protected’ under various tree conservation by-laws – such as those in Leipzig – meaning it can no longer simply be removed. It is certainly more sustainable to seek dialogue in advance and present arguments which, individually or in combination, justify greening, for example as follows:

“Substitute” greening: There is no evidence of previous greening on the building in question itself, but it should be greened in a manner analogous to other buildings in the neighbourhood or region for which such evidence exists, e.g. as a farmhouse with a vine trellis typical of the area or similar.
The greening is required as protection against graffiti.
Greening is important as part of a necessary regeneration of the town centre.
An outdoor seating area is essential for the building’s use as a restaurant; this, in turn, requires greening as a “feel-good” factor
For insects and birds, greening is needed as a bridge to other green spaces within a densely built-up city centre.
Greenery is required as a cost-effective means of drying out buildings, e.g. when a stable is converted for residential use (the walls of old houses remained reasonably dry as long as vines or fruit trees thrived on the building)
When converting a building for residential or office use, summer heat protection is required; full-coverage ivy vegetation is intended to replace air conditioning, etc.

Fear of structural damage

Yes, they do exist and they are unsightly, which is why FassadenGrün provides a detailed description of the structural damage caused by plants. And it is part of every greening specialist’s toolkit to prevent or eliminate such damage through the right choice of plants, well-designed trellising systems and, where necessary, regular maintenance – particularly pruning. Preventing structural damage therefore concerns all buildings and is not a problem exclusive to the preservation of historic buildings, which must be concerned about old, vulnerable houses.

If necessary, today’s conservationists can consult their colleagues from around 1900 to learn that greening dries out the buildings and – provided the façades are intact – does not damage them. The Bavarian “General Conservator” Dr Georg Hager demonstrated this in a lecture around 1913, using many examples he had analysed himself (see “Blumengärten” by K. Trenkle, Eugen-Ulmer-Verlag Stuttgart, c. 1913)

Aside from actual structural damage, there are old wives’ tales claiming that climbing plants make houses damp, allow moisture to seep through, and so on. These stories are outdated, as green facades actually help to dry out buildings rather than causing moisture damage. When climbing plants are planted in the ground in front of an old building, the walls should be protected by a dimpled membrane so that excess water from watering cannot penetrate the foundation walls. More on this on the ‘Ground Planting’ page.

Here, ivy (Hedera helix) has grown beneath some crumbling, old plaster and has caused it to fall away

Patrick Blanc’s legendary “Living Wall” at the “Galeries Lafayette” department store in Berlin in 2010, two years after it was installed

Missed opportunities

Can a building be listed as a monument shortly after its completion? This would be necessary if something special has been created that contributes to the “identity of a place” and will soon become part of the “cultural heritage”. In this sense, the wall-mounted greenery shown in the photos could have been preserved. It was created by the French artist Patrick Blanc and installed in 2008 at the Berlin department store “Galeries Lafayette” as a replacement for a non-functioning large screen.

Apparently, no one thought it possible that the greenery would disappear so quickly. Yet that is exactly what happened when the department store closed in 2024 due to financial difficulties. What a shame, as it was a testament to modern garden art that has now been lost! A similar fate befell a green installation by Patrick Blanc in Vienna at the ‘Sofitel Vienna Stephansdom’ when the ‘stilwerk’ design department store housed there closed in 2017 and the ‘living wall’ also disappeared.