There are certain plants that rarely work well where you put them. In fact the growth can be rather prolific where you least expect them.
Lily of the valley (Nolinoideae) is one although it is good ground cover wherever it emerges. It never really grows in its intended spot. Or seldomly. A woodland perennial it will tolerate shade and is prolific in these areas. Few nutrients and attention. It is drought tolerant to an extent but it would prefer some moisture.
Crocus (Iridaceae), a spring flowering bulb will also pop up where you least expect. Crocuses are very resilient. The plant does grow in a woodland environment but it’s not tolerant of total shade and needs some sunlight. It is spring flowering and low maintenance save periodically dividing not only to propagate but regenerate the plant.
Primula (Primulaceae) is a primrose that doesn’t mind some shade although not full. The soil too needs to be on the fertile side and will not grow in particularly poor soil or do well. The soil needs to be light though needs to have some substance. It mustn’t get waterlogged either, hold enough moisture but be free draining. These conditions aren’t particularly straightforward.
Polyanthus (Primulaceae) also a primrose is very similar and flowers in spring. It can left in the ground or moved / distributed when its divided. The biggest difference is it has more flowers on each stems so the cluster appears bigger. It prefers a more dappled woodland environment. It’s been mooted that a primrose crossed with a cowslip and as a result has become a hybrid
Crocosmia / Monbretia – Valentine flower (Iridaceae) can be planted in one space. A perennial too. It will die back and re surface the following year, a summer flowering perennial. It can be orange, yellow or red. Monbretia is just another more traditional name. More associated with red for some reason. Perhaps the parent before cultivars and hybrids. These clusters can be divided and propagated effectively. Very easy, just cut back dead growth and it will return. It needs a degree of sun though and relatively dry soil, not waterlogged, compact or heavy.
Oat grass (Poaceae) A grass that is said not be invasive. The seeds from the plumes do germinate. An ornamental grass where you usually would cut it to the ground. Divide it to keep the shape, size and vigour of growth.
Everything that disperses its seeds, pollinated by birds / wind / insects can be invasive. It’s perennials on the whole since they have time to establish themselves, source the energy and develop underground. A bigger specimen will never come true, a little “rogue” seedling can be pulled out within seconds.